AnAndTech have a nice review of the MacBook Pro Retina. A few noteworthy things in their review include:
There are also four IO ports, (that’s 2 Thunderbolts and 2 USB 3.0 sockets). The Gigabit Ethernet has bitten the dust, and the Firewire 800 has joined it on the scrap pile it seems.
Somewhat happily, the unit doesn’t get so warm as older models, with a noticeable drop in thermal output (which is obviously only a good thing!). This is in part thanks to Ivy Bridge (from Intel) and Keplar (from GPU giants, Nvidia). The CPU tests showed it to be around 10C cooler than previous models, which is a pretty impressive number.