The first UT has a better feel, and it's not full of fluff to dramatically increase the spec requirements for no reason, thus can be played on my computer. I like the space-y settings the best in UT, so it's boring when the others want to play those cramped, rusty industrial levels.
Quake 3 is still better than both of them IMO (especially with Rocket Arena), thanks to the weapon balance and minimalist presentation - and I only need to see five corners on that horribly complicated decorative structure, not a thousand. Curved surfaces was a great idea for people with low specs.
And I still think any rocket launcher after vanilla Quake 1 feels like firing wet puffs of smoke at your opponents, especially in UT. Q1 was unbalanced, but partly thanks to its audio had a powerful feel that no FPS has captured since.
*In a remarkable display of sudden cooperation, the forumers build a life-size catapult and launch Spiff out of the thread*