It's like "digital zoom" versus optical zoom in cameras, you cannot put back detail that isn't there in the first place.
Just depends, maybe cassette sounds ok to you, and DVD is such a huge upgrade from VHS.
Personally, I think the format war between HD-DVD and Blu-Ray, eventually won by Blu-ray, may yet consign both to history, the true winner being plain old DVD, and the true successor being download or streaming.
My new PC build has some lovely stuff in it (Phenom II 965 BE C3), and I could have put a Blu-Ray in, but it just has DVD.
If I had a monster screen home cinema setup, then I'd be bothered.