What are the best competitive first person shooters on OSX?

Counter-Strike: Global Offensive builds on the strengths of its predecessors, even though those predecessors have been constantly improving for over a decade now.

Nonetheless, Counter-Strike veterans will feel right at home in Global Offensive, albeit with some minor differences. The MP5 is now the MP7, The TMP has left its place to the MP9 and you can't attach a suppressor to the M4.