I second that about Nvidia GPUs. While Linux hardware support is really good, there is plenty of common, mainstream hardware that never was and never will be supported by Linux, usually due to uncooperative manufacturers. For Nvidia, their non-free driver is terrible and the nouveau driver in Linux is hit-or-miss. (Note, many people use either of those successfully, but the likelihood of success drops rapidly with any of: multiple displays, the need to dynamically change outputs, multi-GPU Optimus hardware or even laptops in general, and fully functional hardware acceleration.)