I've had a DP-4000 for well over a year. I like to use a cycle of 3" Hg up to 4.5" Hg and back, in 10 second intervals. I guess what I like best is I can put in on, go back to work on the computer, and just forget about it for awhile.
I've a couple of long vacuum hoses, that I can connect one to another, so I can be out in the tv room, with the pump dutifully sucking away, whilst I am out watching a football game.
It does not need to be connected to my computer; only if I want to change the unit's internal program.