It takes some getting used to, sure, but I'm to the point now where I use it for all sorts of games comfortably, ranging from Civ V to Rocket League to Mass Effect. I'd put it about on par with mouse+kb depending on the game, and I definitely prefer it to a standard Xbox or Playstation controller. The only thing that I wish it could do is work with consoles, but I understand why that would be too difficult to do. I miss my grips and touchpads when I have to use other gamepads though... :/

UPDATE: After a few months of usage the right bumper busted and I am currently in the process of getting a replacement. Unless Valve really messes up the replacement process I still totally recommend the controller though.

Some helpful info:

OS:
Windows 10 & Arch Linux. (check the wiki if you're having issues with legacy games)

Games that I've played that have native support:
Portal 2
Screencheat
The Talos Principle

Some games I've played using legacy support:
Just Cause 3 (Did some long-distance shots with this one, some of the top on the leaderboard last I checked...)
Mass Effect
ARK: Survival Evolved
Civilization V
Battlefront II
DICE's Battlefront (Requires messing with Origin, ugh...)
Rocket League
Fallout 3
Borderlands 2
Spec Ops: The Line
Minecraft
The Stanley Parable