First the good parts: KDE is quite stable for me. I have hardly any crashes... this is huge as Unity had some ugly bugs I could not resolve.
But I had to install the Numix theme and icons and tweak knobs to get a common look between KDE/GTK2/GTK3.. I found the default Oxygen ugly and not well designed but this is probably a question of taste.
With Numix the machine feels and looks great but I'm not so happy after installing Windows 8.1 on an 10 year old Pentium M notebook with 2GB RAM and having to realize that Windows is way faster and responsive and more feature-rich than KDE and Unity and requires less RAM.
I'm not trolling - I'm talking about stuff like browsing files using the file manager and using a browser or office for writing documents.
Back to KDE: I don't understand Plasma at all - I don't use "activities" I tried it but found it useless. I don't care about widgets. I'd care more if the widgets would not be so useless.. something like gkrellm that ran on fvwm95 gives me more and better data about cpu/disk/network usage than any widgets I've found in the collections.
Memory... at least 400MB RSS after a fresh boot running only Konsole. No semenatic desktop, no Akonadi, no widgets... This is just crazy.
I have no SSD and 4GB RAM - maybe I'm too cheap for KDE but Akonadi and all semantic desktop parts never worked for me.
Why can't I disable the desktop search? After some hours googling I managed to kill most of Akonadi and Desktop search but I really would enjoy something like a minimal KDE desktop.
Dolphin/Kwin/Konsole/Kate/Okular are really great tools, through and I enjoy using them more than the Gnome tools..
I don't think I'm an old grumpy user - I really enjoy the Unity concept and even found Gnome3 interesting but I'm still feel some longing from time to time for the speed and functionality of KDE 3.5.
But overall I can work with KDE. I would be probably a lot more happy if I had a SSD and 16GB RAM and well.. that sucks. I don't want to install Windows on this machine for it to be faster!
I know there are alternatives.. but running Windows 8.1 on this 10 year old Pentium M notebook just made clear to me that the problem is not the hardware - it's the software.
Why is it so hard to to have a highly functional and low-footprint system?