Well, it depends. Some of the Ultimate Editions have some slightly large problems, like some pretty serious cropping on 2 films, AVTAK and Goldeneye, and some of the color correction is messed up, like the opening of OHMSS. Personally, here's my list of the best for each film:
Dr. No-Goldfinger: UE (UE has original framing, and color correction is good)
Thunderball: SE and UE (SE has some problems, UE as well)
You Only Live Twice: UE (Good picture and better extras)
OHMSS: SE for film, UE for extras (The blue tint in the opening is horrendous, but it's nice hearing
from caveman Lazenby)
Diamonds are Forever: SE (Picture got really messed up on the UE, not that many new extras)
LALD-TMWTGG: UE (Great new extras, mostly improved picture, except for the orange tint in
LALD's titles)
TSWLM: SE/UE are about the same (SE has grain issues, UE has blue snow in Austria)
Moonraker-Octopussy: UE (Roger's commentaries are really fun to listen to, and picture looks good)
AVTAK: SE (WAY to much cropping)
TLD-LTK: UE (Correct framing on UE)
Goldeneye: SE (See AVTAK)
TND-DAD-UE (Nice, upgraded picture over the SE)