I have to say I prefer the no hand models.Except on packs like the L4D weapon pack and GCats. Mostly because they have a more realistic feel, and they would look bad with only one hand.And they usually don't look to bad on handguns.
I find it nice how people such as Rykuta take the time to animate the reloading animations with all the hands and such.
hands on models look horrible and if you make them then you're bad at making add-ons