I have a V3840 for a year or two now. Seems to work just fine. If I am sealing a lot (like 20 bags) it seems to go into a protection mode and needs to rest for 10 minutes. But other than that the only problems I've had are bits of food in the seal causing it not to seal.
Proudly Smoking on a UDS, PBC &
Accidental Winner of the 2012 "Saucy" Throwdown.