IMO, these sd work 'like a VCR' as far as recording and playback. There are models w/ harddrives, VHS players, etc. built in, but to me that's overboard.
Bells and Whistles
The VHS option is not bad, but you most likely already have one you can plug into inputs of DVD recorder.
I have a DVD recorder for archiving TiVo shows as opposed to accessing my TiVo from my PC. This is nice because it means I can also archive VHS tapes, camcorder tapes, etc. w/no extra work.
I do have a TV card in my PC so I can do this, but using DVD recorder is easier.
My motto is: buy what you WILL use and not what you CAN use.
I've bought lots of things that CAN do a lot, but in reality I don't use all extra features. Not in all cases, but in this case, I say pass on bells and whistles.
Again, there are models w/ all types of features, but if you buy one that is a DVR, DVD recorder, VCR, TV tuner all in one and one part breaks, it's all broke.
Realize Something About Technology
Remember - this is new technology and will only get better and cheaper. If you buy top of line today, it's going to be out of date and/or cheap tomorrow. Test waters w/ a 'good' model and upgrade when time is right.
Editing Your Recordings
Chances are - you won't. It's a pain for most part and usually requires DVD-RAM or DVD-RW discs to do it and they're more expensive. If you have a lot of free time for this, you're a rare person.
I was looking for this type of solution in getting ready for having a baby and I knew I wasn't going to be sifting through and editing hours of video.
If you're really interested in editing, look in to PC options. Pinnacle, ArcSoft, Adobe, etc. - they have good solutions for that.
DVD+R, DVD-R, DVD-RAM, DVD-RW
DVD+R and DVD-R are like VHS and Beta: they're both ok right now, but eventually we'll probably land on one or other. It seems to be leaning towards DVD-R which tend to be less expensive also.