The MacBook Pro is a nice machine. The screen looks great, it's made of glass and metal, and years later the performance has kept up. I have a Model A1398 with a retina display and thunderbolt ports from late 2013. The moment I got it I installed Ubuntu 14.04 and haven't looked back.
Apple isn't concerned with Linux compatibility so a few proprietary drivers are necessary to get the important stuff working.
Once you boot up you'll need to plug in an ethernet adapter. Once online install your updates, open up "Software & Updates", and install the latest proprietary closed source drivers for your Broadcom WiFi adapter and your nVidia graphics chip.
There are also a few other little problems to fix...
The track pad will freeze up randomly from time to time. Just install this.
sudo apt-get install xserver-xorg-input-synaptics
To get your screen and keyboard backlight adjustment working you need to add this command to your
@reboot root sudo setpci -v -H1 -s 00:01.00 BRIDGE_CONTROL=0
Also the webcam doesn't work. I consider this a feature. If you really care these guys have been working on a driver.
I got the tux sticker on etsy.