Fun with toys and fingers and such, but with other men, it's overrated. I've tried it a few times, and it just wasn't enjoyable. Usually one cock just sits there while the other does all the pumping. And it's rare that both men will sync up enough to work up a good rhythm. So no thanks.
I don't think I could ever do it with my wife, although I would love a MMF threesome with my wife, I think dp treats a woman like an object whereas I'd like to see them woman in charge of the pleasure.