I just got the mid-range 13" retina today (the one with 8 GB ram and 256GB SSD) and I'm pretty happy with it so far.
I loved my 2009 13" MBP, and upgraded it with a 128 GB SSD and 8 GB ram a while back and gave it to my wife. It's still chugging along great, and it handles anything we throw at it. She doesn't game at all, so it's more than enough.
I got this to be my main computer, do some web dev stuff, and a bit of gaming too.
The screen is pretty amazing I must say. That's the biggest difference I noticed. The keyboard is a little nicer too, with quieter keys and a shorter travel distance to register a stroke.