Neither, Tribes 2 ownz them both

T2 has owned ALL of my free time for the past 2 days (I just got the beta).
The player models, air vehicles, land vehicles, explosions, weapons modeling, water modeling (including waves and physics), clouds, weather effects, and graphics engine in general is FAR Superior to UT and Q3. It must be seen in person. The screenshots just don't do it justice.