I can only say that I'm loving my Blu-ray copy! It's by far the best viewing option for fans who don't feel like paying over $100 or more per episode for the old DVD releases. I hope the BBC continues to put them out, and I'm more than willing and ready to part with my cash!
EDIT: Yes, I realize these are available for download, but they don't look as good...I don't guess it matters though. The old Doctor Whos are probably best viewed on an old and dying CRT set...or on aged VHS. There is a certain romanticism to that...I will allow it.