Hi Michael555 and welcome to the forum
The question as to which will give better results - ADVC100 or DVD recorder is impossible to answer really. The problem is that although the AVC100 is an excellent converter there are just so many different DVD recorders and some will also do an excellent job. To decide which at the end of the day gives the best results would require a side by side comparison which I have never done. But as I have said, they should both do a reasonable job of conversion.
The down side to the DVD recorder is you then have very limited editing options. Some basic editing can be done on the recorder if it has a HDD built in and you can always transfer the files from a DVD onto the PC. The problem with this is that the files are highly compressed when written to the DVD disk and therefore you will loose a fair bit of quality once you start editing, if any editing is required that is.
So all I can really offer as advise is to think hard and go with what you think will work best for you. It is very true that once all your tapes have been converted then you are unlikely to reuse the ADVC100 but a HDD/DVD recorder will be used to record from the TV etc. But on the other hand if you need to edit the captured footage then you will loose quality via the DVD recorder which you have stated you don't want to do. Some editing software will loose only a small amount of quality, but the down side is to achieve this the edits are no longer frame accurate.
Mark.