The Q3 engine is far superior for good action and control. UT is kinda slow when it comes to hardcore action.
But playability... that's something else. The weapons in Q3 are useless and boring. Period. An ASMD, minigun or a flak cannon beats all weapons in Q3 EASILY.
Too bad they cannot combine all good stuff into ONE game....
But hey, I play both!!! (And I kill you easily)
When it comes to bots, Q3 is a joke even if they are harder. But that is because THEY ALWAYS HIT! Not at all like a normal person. Easier bots are just more Stupid with a capital S!
UT bots are far more convincing, sometimes you cannot see who is bot and who is human (except the bot is named Archon and has 0 ping...)