I really don't use any Apple software on my rMBP except for the OS... and even there improper handling of Bluetooth and WiFi are unacceptable. I went with another macbook because I love the touchpad, and like an all-metal case. That said, I paid through the nose for something with an OS update that's simply unreliable.
It will be the last Apple product I buy for a long time, and TBH, if Ubuntu comes out with a good experience on Apple hardware, I'd probably switch the OS out.
Part of it is most of the linux friendly laptops I don't like... There's a few points.. one, I like a larger touchpad, with whole-pad clicking... other than the chromebooks, and my logitech htpc keyboard I haven't seen this (I also don't like the region based right-click)... The touchpad is a huge issue for me.
Second, I REALLY don't like either the Fn button being in the corner (muscle memory), or anything obstructing the right shift (again muscle memory). As it is, I hate most laptop keyboards.
Third is the display, I actually really like the retina display itself, and it allows for scaling VMs very nicely. Probably the closest in terms of hardware to MBP would be some of the Asus and Acer ultrabooks, which I'm not entirely opposed to, but then it's still hit and miss on hardware support.
What I would love would be for Ubuntu, or someone much more familiar with their installers to create an installer that would just detect that it's apple hardware, and make it all just work... that would include bluetooth, wifi, proper touchpad drivers/configured in the box.
I really like my rMBP hardware wise... but going to something with different headaches won't exactly be better.
It will be the last Apple product I buy for a long time, and TBH, if Ubuntu comes out with a good experience on Apple hardware, I'd probably switch the OS out.