Thanks for the tip on Revision. I may not have even noticed it. I now have a third reason to choose PC... mods.
Yes! I've played total conversion mods (this type of mod is equivalent to a full fledged game) that outdoes AAA games in the areas that really matter, like writing, quest design, gameplay, art design, originality, longevity, attention to detail in all of these areas, and even soundtrack believe it or not. This one called Underhell is one of the absolute best FPS games I have ever played, and I've been playing FPS since the late 1990s.
http://moddb.com/mods/underhell/
Many of the best multiplayer shooters began as total conversion mods too, like Natural Selection 2 (the first one is a mod for Half-Life) which I rank in the top 3 best PvP shooters of all time, Rising Storm/Red Orchestra 2 (originated as Red Orchestra, a mod for Unreal Tournament 2004), Killing Floor/Killing Floor 2 (originated as a mod for UT2004), No More Room in Hell (free standalone mod on Steam).
Right now I'm playing a community made adaptation of The Temple of Elemental Evil (which was a 1985 pen and paper RPG module), and it is considerably better than any recent commercial video game RPG I've played. So this modding excellence extends to many genres.
On a side note, most people don't know that most mainstream popular video game franchises began as PC exclusives. Examples include Call of Duty, Battlefield, Fallout, The Elder Scrolls, Grand Theft Auto was technically released on PC first but the Playstation release came very shortly after.