Minecraft is not bleeding edge graphics, but it is written in Java and takes a huge chunk of system resources to run.
I tried GNU/Linux as a desktop operating system (about a dozen different distros) and settled on CentOS 6.x, but I only use that for dev purposes at work.
GNU/Linux is still a bunch of different software written by different people trying to work together. There are always apps that look, feel and operate differently, kinda like on Windows. At least on Mac all apps look and work basically the same.
But ... on Mac sometimes I miss the ability to customise the desktop a bit more.