The graphics on Q3 seems to be slightly (reads very, very slightly; asymptotically so) superior than UT, but that is where the positive comparisons for Q3 stops.  UT's map is a lot more creative (including such  settings as a moving train, underwater base, and an old wooden ship), and  the variety of options other than deathmatch (capture the flag, assult,  etc.) puts Q3 to shame.