Well, my DVD recorder is a Panasonic DVD-RAM/DVD-R one. With DVD-RAM it's problematic since OS X doesn't recognize the UDF 2 disc format, and I don't have software that works with the DVD-VR files. (I have to do the video extraction on my PC.) (And yes I have a DVD-RAM capable drive for my Mac.)
With DVD-R, it's less problematic, since the discs are standard DVD Video discs, but you still have to use 3rd party software to rip the video to MPEG-2 format from the original .vob files.
Once you have the MPEG-2 you have to demux to separate audio and video files. (Or I suppose one could go from the original .vobs on the DVD-R directly to separate MPEG-2 video and audio files.) I haven't tried QT 6.3 yet, but with older versions of QT you had to do this because for some strange reason if you simply tried to convert an MPEG-2 with muxed audio in it directly to a .mov file, the audio would disappear. Thus you have to extract the audio first and then add it back in later, in iMovie. Very irritating.
With a Pioneer DVD-RW/DVD-R standalone machine usually you'll run into the same issues. DVD-RW on the Pioneer will have the same function as DVD-RAM on the Panasonic. Same DVD-VR file format and same UDF 2 disc format. I think there may be a way to use DVD-RW on the Pioneer like DVD-R (not sure), but the problem with that is you lose most of the editing functions. The whole purpose of UDF 2/DVD-VR for both DVD-RAM and DVD-RW is for very flexible editing.
With a Philips DVD+RW machine, the +RW discs are in many ways treated like DVD-R, but again, the editing functions on that machine are very restricted. (ie. Editing on +RW is much less flexible than on -RW or -RAM.) Plus there are some issues trying to read + media on some Macs.
What a lot of people are doing nowadays are scrapping the desktop computer all together. They just buy a
Panasonic DMR-80 DVD-RAM/-R Recorder with a
built-in hard drive. Some additional info is
here. You should also check out the
www.dvdrhelp.com website and Mac forum, as well as the
www.avsforum.com DVD Hardware section.
ie. Record the TV shows to the Panasonic's hard drive. Then edit the clips directly on the hard drive. Then make a DVD-R on the Panasonic directly using those edited clips. I've never used one but I'm told it's MUCH easier (and faster) to do it this way with no complex muxing/demuxing conversion, etc. required on the Mac. You just don't get the pretty transitions and menus that iMovie/iDVD offers. (There is still a menu, but it's fairly boring.)
If you want to make copies of that DVD-R, you can do that on the Panasonic, or else you can just make a disc image of it with Toast on your Mac and copy away.
What I have been doing actually is somewhat similar. I record my shows onto DVD-RAM on my DVD recorder. Then I edit those clips directly on the DVD-RAM. Then I take the DVD-RAM and stick it into my Panasonic RP91 DVD player (which supports DVD-RAM) and record the output back onto DVD-R on my DVD Recorder. Obviously it'd be a lot easier if I had a hard drive right in my DVD recorder.
I hope that answers your questions.