Another big issue I've found with the Retina MacBook Pro is the power consumption with Linux. From ACPI information and also testing when on AC power using a USB-based WattsUp power meter, Ubuntu 12.10 is burning through noticeably more power for this Intel Ivy Bridge laptop than OS X. Ubuntu was going through ~20% more power than OS X. Under OS X there's an Apple rating for this rMBP backed by an 85 Watt MagSafe 2 power adapter for it to last about seven hours on battery, but under Linux you'll see a much shorter duration. When Nouveau ends up working for open-source NVIDIA graphics on this laptop, it will be even shorter since Nouveau doesn't yet have proper dynamic power management support for notebooks.
Linux burning through much more power on MacBook Pro notebooks than OS X isn't terribly surprising. Prior to this new laptop, I was using a late-2010 MacBook Pro and there I ended up running Ubuntu Linux virtualized atop OS X 10.6 since that's where I found the best battery life. Running Linux bare metal caused the notebook to go through noticeably more power than running OS X and virtualizing Ubuntu full-screen with VMware Fusion. With the Retina MacBook Pro there's more power to burn when virtualizing Ubuntu 12.04 LTS with VMware Fusion 4, but it's still much better than running a broken Ubuntu 12.10 desktop on the hardware itself.
In the end to actually use Linux with the new Retina MacBook Pro in a production capacity, the only sane manner to do this is through virtualization. For virtualization, I still find VMware Fusion to be the best in terms of features and support along with performance. The virtualized graphics performance is much better with VMware Fusion than using Oracle VirtualBox on Apple OS X and even the CPU performance is better. Running OS X 10.8 (there's some performance improvements with OS X 10.8 Mountain Lion) with virtualized Ubuntu 12.04 LTS using VMware Fusion 4.1 is what I've successfully been using now to get the most out of this $2199 USD laptop. In terms of the retina display when using VMware Fusion, rather than fumbling with the text-scaling-factor and other settings, I've found the best visual appear to be running the Unity desktop full-screen but using a resolution of 1440 x 900 rather than the native 2880 x 1800. OS X is still running fine at 2880 x 1800 but the VMware guest resolution as controlled through the "vmwgfx" Linux driver is at half the resolution. Using virtualization also avoids the Linux Thunderbolt shortcomings when using the 27-inch Thunderbolt display in the office.
If you're not willing to entertain the possibility of running OS X on the Apple Retina MacBook Pro and then virtualizing your favorite Linux distribution, don't purchase this latest Apple hardware or stave off the order for several months. With Ubuntu 12.10 final in October it will be too late for any decent "out of the box" experience on the hardware since many of the recent rMBP patches for providing better Linux hardware support still aren't mainline. With the Linux 3.7 kernel (the 3.6 kernel is still in development but past the merge window already) may offer somewhat of a fine "out of the box" experience but even at that point the switchable/hybrid graphics will still be less than stellar and power consumption will likely remain a big issue. If you're after a clean Linux experience on the Retina MacBook Pro, it likely won't come in released distributions until early 2013. There's at least work by upstream Linux developers going in the right direction for supporting this hardware, but unless you're an experienced Linux enthusiast and willing to jump through several different steps and using non-stable patches, the experience is not reasonable for end-users.
With Ubuntu 13.04 in April there will hopefully be good Retina MacBook Pro for this mid-2012 laptop, but at that point it will be the better part of one year old and it will be right around the time Intel releases their new Haswell processors where Apple will surely follow with Haswell-based Retina MacBooks. If attracted to the MacBook Pros for their very slim and lightweight form factor and retina display, one can only hope more vendors will follow soon with nice Intel Ivy Bridge Ultrabooks and/or that Linux has caught up by mid-2013 so the time to supporting Haswell MacBook Pros will be much shorter. The only optimistic news out of all of this? By the time that Linux fully works on the hardware, Apple will probably have by that point dropped the prices of the retina-based hardware.
Additionally, Apple's new 2012 MacBook Air isn't trouble-free on Linux. If anyone has any other specific Linux questions for the Retina MacBook Pro, ask via @MichaelLarabel on Twitter.