I agree with all who said this is an apples to oranges comparison. The Floyd were masters of sound-scaping, Deep Purple were masters at creating balls out hard rock. I consider the two bands equal, for they were both masters at their particular niche. I love David Gilmore's style, but Ritchie Blackmore is a far better technical player. Rick Wright is a good Hammond player, but Jon Lord is a phenomenal Hammond player. Where Rick Wright shines is his abilty to integrate a grand piano, electric piano, Mini Moog, ect,...more than just a B3 player (Jon Lord didn't start using a Moog/electric piano until the Burn/Stormbringer days). Roger Glover is a better bassist in my opinion, but Roger Waters earns extra points for being both a singer/songwriter in addition to being a bassist. In fact, Pink Floyd as a band earns some extra points for having three out of four of it's members sharing vocal duties. Nick Mason and Ian Paice are pretty equally matched, but Ian Paice earns extra points for using a minimalist drum kit.
This is the break down of why I think these two awesome bands are equal.