It manages to pack a lot of power in a very small package. And the Open Movie/Open Game projects help to drive the direction of the Application with concrete goals. Personally I think it's one of the media production suites out there for the hobbyist. The power + price (free) can't be beat for the non-professional.
The Python API could use a little work, and takes some getting used to, but it's also incredibly powerful. You can generate geometry from a Python script. You can script movement..anything.
I would go one further and say one of the most successful and best run projects in Open Source. I have always been impressed with the Blender developers ability to just plain deliver. Features get built quicker than you can keep up with them, and they seem to have had the best success integrating GSoC projects & developers into the code & team I've seen.
I don't know what their secret sauce is (Ton's enthusiasm?) but I think many projects could learn a lot from them.
/rant
I happen to like Vim which perhaps explains why I like Blender. Blender isn't really designed for the dabbler. It's designed for the serious user. For that type of user it's worth the learning curve since you can get really fast in it. So fast that a common activity is speed modelling. If you only dabble then something like SketchUp is probably more your speed. If you plan to create stuff like this: http://blenderartists.org/forum/attachment.php?attachmentid=... though then blender is well worth the learning curve.
Just because a UI is powerful does not mean it has to be unintuitive. Unity is a very powerful game engine and it has a very intuitive UI to the point where if I'm just fiddling around with it I can generally figure out how to use it. Blender is pretty much the exact opposite. It comes down to cost vs time. Do I want to spend time to configure Blender or do I want to spend money and buy something that has a much more intuitive UI and use something that I can just get started with right away? For my sanity I would choose the latter.
Just because a UI is powerful does not mean it has to be unintuitive. Unity is a very powerful game engine and it has a very intuitive UI...
Let's not confuse the power of a software package with a powerful UI. Blender is the emacs/vi of 3D software - its UI is very unintuitive for beginners but extremely fast (and intuitive) to power users. Personally, I found that with Blender it's hard to master the basics but easy to learn the advanced stuff, once you have your basics down. With other packages I've used (3d max, Maya, Softimage) it may be easy to do a simple scene, but advanced stuff is very unintuitive to the point that you need a tutorial to do anything you haven't done before in that particular package.
Did you watch any video tutorials?
What 3d apps do you like?
When I started about 15 years ago, Blender was much less intuitive and there was little tutorials and help. It helped that I used 3ds r4, 3ds Max, Auto Cad, and VIM... It still took many hours over a couple years to become comfortable with Blender.
They've since made everything MUCH more discoverable and organized. I've seen and helped young kids get started with it. I've also used/still have to use 3ds Max, Lightwave, Maya and others ...but Blender is my creative swiss army knife.
It's not perfect, but for ~95% of what I need it is... and it's still improving. Ton Roosendaal and others involved with this are awesome. I donated some to see it open sourced, and some since. My best investment ever.
S is scale default in BLender.. S is "Set Key" in Maya that will only use up that key for ONE aspect of model creation right out of the box.
Blender's shortcuts know what to do in context.
Some of the defaults are just downright stupid: why does rotate by default rotate in screen-space (so against the 2D camera plane, instead of world or object space). The reliance on the MMB so much (Maya does this a bit as well, but there's keyboard alternatives) means it's almost impossible to use on a laptop. There's so many things like this that while minor in isolation are just so frustraiting as a whole when attempting to use it, and make me go "nope, I'll go back to Maya or Houdini thanks".
Blender itself is powerful, yes. But that is in spite of its terrible UI. Most of the controls don't even have useful tooltips.
To be fair, they are improving it slowly but surely.
Now having to work with Maya is the exact opposite. Everything is a mouse click, menu selection, popup window, menus repeated over and over and over again. 5 ways in Maya to do the same action.
In Blender, you can extrude and instantly have access to scale and transform, in Maya you must select a tool to do it right after. Extra clicks extra time.
Insert Edge Loop in Blender requires one click, roll mouse to select how many you would like to add, T or F6 to bring up a menu should you need to do something special. Maya, you have to keep changing the menu settings to do equivalents.
A simple inset action is easier in Blender. In Maya it takes two more clicks and tool changes to get the same, or you have to constantly be working in the "Modeling toolbox" which clashes with other menus should you use them.
SHIFT-R to repeat last action (not just last tool) which is not available in Maya, and only repeats the last tool.
Viewport Navigation in BLender: No clicking on boxes, hit 7 to go to Top orthographic view... then you can roll out of it immediately back to perspective. Maya won't allow this... you must Space->Select a window to return to a view.
Extra clicks extra time.
Plenty more examples of how Blender accelerates your workflow by removing unnecessary menus and elements gobbling up real estate.
Blender is for shortcut masters wanting to get stuff done, Maya is for menu and button clickers.
A UI is for those who first access a software. And it has to provide instant understandable access to basic features without reading the manual. Every advanced feature can be hidden (clicks away), but the basics must be there.
If that is not the case and you have to learn the hotkeys or diggest a dozzen tutorials - well then there is no GUI.
I take the point that it's powerful once you learn the keyboard shortcuts, but it really shouldn't be either/or, especially for beginners.
My issue with it is that the API is so unwieldy. I'm very interested in creating fun things with code, and it's actually easier to do that in some of the pro packages than in Blender.
I gave Blender a shot several times already and have never gone through much of it out of frustration due to UI. That's telling something considering all of these apps I've been through over the years - just consider some of the UI catastrophes those had.
I understand Blender now has much of capabilities needed in daily production, but that UI... Damnit.
</rant2>
ps: I never got to use old software like TDI or 3Ds, I started around Maya 2, the best I could get was this https://vimeo.com/9652184 and that www.youtube.com/watch?v=QWzITPB4mzc
CATIA? So I looked at CATIA and a cursory glance shows that they aren't all that conventional either. One shot I saw was of v5 with a bunch of tiny floating undockable overlay windows. Yeah great UI. The catia sketch tool seems awesome, but that seems to be a smaller subset of the software for prototyping stages. I realize maybe it's unfair to ask, but is there an ultimate video walk through that you think showcases the great UI of CATIA? Does CATIA also have all the features and expectations that blender has? Such as animation, advanced texturing, lighting features. It certainly seems to be a capable modeler based on some final render images I've seen and it probably allows for physic simulations I'd gather
You can do everything you can do in Blender also in CATIA (except fluid physics, game engine) but you can do advanced simulation like finite elemente physics and electronics. Also CATIA is a CAD software, so there are of course differences and it will usually take longer to create a 3D model, but afterwards it can be built in real world with real world physics.
It's UI paradigm in particular is at first somewhat overwhelming and unintuitive, and then suddenly with the tiniest amount of instruction or direction perfectly understandable and infinitely flexible (once you "get" how it works you can imagine them adding any feature and it being just immediately, simply usable)
Here's an (out of date) overview of the hotkeys:[1] Some of the hotkeys change in each new release. In typical open source fashion, the "solution" to that mess was to make the several hundred hotkeys remappable: "Important note: the ever changing nature of Blender's development means features can be arbitrarily updated so shortcut keys may be mapped to different functions or be in different locations version to version - this is especially true of Blender 2.50 up to and included the latest versions."
If you like EMACS, you might like Blender.
From a developer perspective, the Blender game engine is interesting. An idea that keeps coming back is that programming should be done by wiring little boxes together in a GUI. The Blender game engine does that. This leads to giant, messy wiring diagrams.
[1] http://www.katsbits.com/tutorials/blender/useful-keyboard-sh...
Regarding hotkeys, there were some major changes for 2.5 along with other UI changes, but after that the default have barely changed, just additions and minor changes when the underlying features change.
Making hotkeys remappable was in no way a solution to that "problem", it's a standard feature in other 3D software that a lot of users requested, especially those who wanted to make the hotkeys compatible with Maya and 3ds Max.
I'm pretty pragmatic about tools, everybody has a preference and outside of pipeline integration issues it's the speed and quality of the output that matters.
For me, what's given blender the edge over the commercial software I've used (mostly Maya) is the keyboard-driven approach:
I can rotate a cube 22 degrees in the x axis, scale it 15% and move it 3 units in the z axis in about 5 seconds without every reaching for the mouse. That's tremendously powerful and fast, and requires that I know only about 4 keyboard shortcuts.
It's a bit of a learning curve (no moreso than learning, say a new programming syntax), but when you catch on, the speed and efficiency pays for itself in short order.