Just to put in my two cents.. Yes, most Miele products are very good for allergy sufferers.. however their uprights are HORRIBLE. (my own opinion) They are very awkward, hard to steer, big and clunky, and what I hated most was that swivel neck which made it that much more difficult to maneuver. What was most annoying at the time was that my dealer was really pushing me to get one. Glad I didn't.
If I had to choose between their canisters and uprights, I'd definitely go for the canister, and I'm not really even a canister person.. They're much better designed and have a less complicated air path; which means fewer clogs. I've also heard of several issues about many parts breaking prematurely.. I almost feel as though their uprights need to go back to R&D. I do not recommend!