I have tried a few different DVD readers, but have never found one that does the job very well. None read DVD's as well as DVD writers.
Never use on-the-fly (disc to disc), because unless the disc is brand new and spotless it will almost certainly fail (and even does sometimes with brand new discs).
The software you use to bac up DVD's depends upon the stuff on them. If it's just a DATA DVD full of files such as MP3s etc you won't have many problems, but if it's a video DVD you will stuggle. Especially if it's been used a few times.
Also if you didn't know retail DVD's are around 9Gig in size so can't fit onto standard DVD's so you will need to compress the video first using software such as "DVD Shrink" I've got a dual layer DVD writer so I can write to the larger capacity discs, but they arn't cheap
Q. DVD's are bigger (10 Gig or so) but blank DVD's are only 4.7 GIG. How can I copy them? A. This program alows you to take out all the crap such as foreign subtitles and it uses a kind of compression to shrink the film to a standard blank DVD disk. Personally I can't tell any difference in quality.