As the owner of an 8 month old early-2013 rMBP 15", and especially as someone prone to new product envy, it's nice to see that the new models don't blow the old ones away in performance. I'm generally quite satisfied with the battery life on my existing computer, and Mavericks not only seems to have improved on this slightly (pending more extensive testing) but fixed a lot of the annoyances with this computer under Mountain Lion.
I'd ordinarily head straight for the "Waiting for Broadwell!" camp, but I'm happier with this computer than I have been with any other computer for quite some time.
Im in this camp too, although unlike all my rMBP friends (most of whom have 2012 edition) Im not overly happy with my machine. You know when you get a computer every so often that just seems slightly cursed? Everyone else says theres doesn't miss a beat, never jerks, doesn't slow down. Mine gets to a point after a period of being booted where its 16gb of ram have gone, its using a 10gb swap file and its beach balling, especially in Safari.
Now I do multi-task hard but I'm not hitting those CPU's overly hard and my iMac takes everything I throw at it silky smooth, including multiple VMwares - all I have to do is run the iPhone sim on here and the computer is crying. So either I expect too much (my iMac is 2011 and scores slightly less in geek bench) or this machine is a touch of a dud.
So with the A/C wifi, the improved battery, Thunderbolt 2 and most importantly getting rid of the Intel 4000 which I don't think was ever capable of moving retina pixels I was ready to take a hundred quid hit and upgrade, but like you Mavericks on initial inspection seems to have sorted a lot out, especially the smoothness and animation side of things. I can now jump into mission control at any time it seems and it animates properly rather than at 2 frames per second!
