Just like you are considering, I recently upgraded from a 2007 MBP to the current retina one.
The biggest changes for me:
- the retina screen really looks gorgeous, makes text look great
- the ability to switch effective resolution between normal/web browsing and high-res/small icons/coding mode is really useful
- since it has no hard drive, it runs really quiet, which is nice. unless, of course, the fans kick in - they are fairly loud, but the fan really sounds different in a less-annoying way, less like a jet engine and more like white noise
- the keyboard feels different, since the keys are very flat with little travel. Not sure yet if better or worse than my previous macbook's non-chiclet keyboard.
- the power-to-weight ratio is great - but it's not the lightest notebook, so if you don't need all that much power but need to carry it with you a lot, you'd probably be served better by a macbook air or zenbook prime.
- I need an optical drive surprisingly often, so I got the external usb superdrive. Also, needing to carry extra cables to get ethernet or more than 2 usb ports is annoying
So far I'm really happy with it, especially the retina screen is something that I really enjoy, and that you can't get with any other manufacturer or model.
Is it worth the money? For me, yes, since I use my computer a lot, and tend to keep it for many years. But you could probably get a computer that's 80% as good for half the price...