I have one. For DVD to DVD copying, stay with the computer, no doubt about that. You can edit stuff out, move stuff around. With DVD to DVD copying on the entertainment center, you cannot get all your menus, navigation, etc.. Basically movie only, and the quality will not be as good.
I use mine strictly for copying some VHS tapes to DVD. Has worked on all tapes I have tried it on.
If you copy on the computer, in addition to the 2 utilities you mentioned, you'll need something like AnyDVD for protection elimination. I also use CloneDVD2 for splitting discs, in the rare occasion I want to.
Well, obviously your quality on your DVD copy of a VHS tape is only going to be as good as your VHS tape. If you have a crappy tape, the DVD copy will look the same.
Do a head clean on your VCR, run a tape and look at the quality Record in the highest quality mode of your DVD you can, and see what it looks like. If you aren't happy, give the thing to your girlfriend. Or use it to help her copy her tapes to DVD.
Once you get the video onto DVD, you can edit the video on your PC much easier.