Unreal Tournament vs Quake3

Unreal Tournament(UT) is a multiplayer online first person shooter. It came out competing head-to-head with Quake3. Many people purchased both. Others are rabid fans of just one. The truth is the two are extremely similar.

The models and skins in UT are lacking, compared to Paul Steed's impressive work in Q3.
It does have more gameplay types out of the box than Quake3, however.

In truth, although you will find few in either game's community to admit it, the two games, UT and Q3, are nearly identical, and both very unoriginal.

The differences:
• Quake3 is prettier, and includes curved surfaces
• Quake3 has quite significantly better models and skins thanks to Paul Steed
• Unreal Tournament has two more gameplay types, Assault and Domination
• Unreal Tournament has slightly different weapons
• Unreal Tournament has secondary fire modes.
  

That is REALLY IT, besides extremely minor physics and mechanics differences. Overall, it ends up just being a random matter of your taste in FPSs.
The smart people are still playing the good mods for Quake2 or Half-Life, and waiting for any must-have mods to be released for either UT or Q3. Chances are the same mods will be released under different names for both. The real test will be to see which of Q3 and UT provides better support to the mod-making community.