<< As for the video out, is it any better than than the one in my 3d prophet 2 pro? >>
Absolutely. The TV-out quality on the Hollywood Plus (DXr3 is the same board) is far far better than the Brooktree chip on your GeForce. It's very noticeable in my opinion. The Brooktree chip doesn't look any better than a decent VCR. The hollywood plus/dxr3 is as good as a set top DVD player.
Side Note: The Rage Theatre chip used in some of the newer ATi board (Radeon AIW, Vivo and the AIW Pro32MB are the only ones I know of off hand) are quite good TV quality, almost as good as the H+/DXR3. But the Brooktree chip is quite a ways behind (some GeForces use a Chrontel chip which I've never personall used, but have heard is a little better than the Brooktree, but still well behind the H+/DXR3).
Try the TV-out on your GeForce, it's not near as good as the Decoder board, but depending on your TV and how discerning you are the GeForce may be good enough for your liking.
And the Decoder card definately hurts 2D monitor quality. For DVD display on a monitor Decoder cards are a bad choice, software can do just as well if you get a good player, and you keep 2D quality at max. But for TV quality you can't beat a hardware decoder.
Edit: Just a random sidenote that has nothing to do with anything, using a hardware decoder is a pain in the arse to use for TV-out anyways. If you want TV-out get a set top...much much easier.