I own 3 Liftmaster units:
A 3800 that has been operational for about 3-4weeks.
A 3280 that has been operational for about 6-8 months (belt drive)
An older 1/2 horse chain-drive unit that came with the house.
As mentioned above there IS a cable-bump devise on the 3800, that should solve any problems. In the time I have owned the opener we have had ZERO problems with it. It is on a 10X10 fully insullated sandwich door on a high-rise track. I have even stood under the door and pushed up while NOT breaking the beam (essentially causing a cable bump), as stated above, it just stops. I also like the locking bolt that shoots through for security. As for sound level, I don't think I've EVER heard a quieter opener.
The 3850 is SUPER quiet and reliable as well. People always comment on how quiet it is (at least until they hear the 3800 run). If you're going to go with the traditional I would step up to the 3/4 horse model, there's not that much difference.
Long story short: unless the 3800 develops major problems, I will be replacing any failed/future opener purchases with 3800's or their like going forward.