What are the best competitive first person shooters on OSX?

Even though old maps have been revisited and improved by a wide margin, new maps and modes released with CS:GO are pretty mediocre.

Half of the maps available are locked under Arms Race (which is a re-imagining of the original community-created GunGame) and Demolition (GunGame without insta-respawn and bomb defusal) modes.

These game modes feel pretty safe and unimaginative, especially for veterans who have played their predecessor.

Some of the new maps are pretty compact and designed to act as instant-action meat-grinders akin to modern FPS (like Call of Duty) instead of requiring any tactics to win.