When it comes to the switchable NVIDIA/Intel graphics on the Retina MacBook Pro, that's a big mess too. There isn't any working solution for dynamically switching between the graphics processors in any sane manner and that both the open-source Intel and Nouveau drivers fail to properly control the hardware in a standalone manner. Using the NVIDIA binary driver will work for the GeForce GT 650M on the Retina MacBook Pro, but switching to the discrete NVIDIA GPU requires booting OS X and using a utility for manually switching that GPU to drive the display. There is work towards switchable graphics along with related work like the DMA-BUF PRIME happenings, but we're still several months out from all of the pieces being mainline and becoming a reality. Ubuntu 12.10 won't have these components but hopefully there will be some early support in Ubuntu 13.04. The Nouveau "Kepler" support is also still forthcoming with no proper micro-code support and the re-clocking support and power management being non-existent.
For using suspend-and-resume under Linux with the Retina MacBook Pro, you must also be using the NVIDIA binary driver. One of the noted limitations for the Retina MacBook Pro with the NVIDIA binary driver is that there even the black-light control isn't working.
After working out these issues -- which would certainly be a headache for any novice Linux user -- the state was still less than ideal due to the non-switching graphics and other minor hardware support issues (e.g. broken integrated microphone support). The various Linux desktop environments are also less than ideal in handling high-density displays. Compared to OS X 10.7/10.8, the Unity, GNOME Shell, and KDE desktops all looked like shit at 2880 x 1800 on the Retina MacBook Pro. The text was difficult to read and even when toying around with different scaling factors, the text ended up looking awkward in relation to icons and other visuals. Hopefully as these "retina" displays become more common among vendors, we'll see more work by the Linux desktop developers on properly supporting these high-density displays.