What is the best upright vacuum cleaner?

I work in a vacuum repair store, and for me, in my opinion, I would NEVER own a bagless. They are dirty to empty, cost quite a bit for all the filters, and seem to lose suction quickly. Now, the Dyson is advertising that they never lose suction, and while I never tried one, I know it is virtually impossible to get parts for it. My money, for a vac at/or under $200 is the Panasonic. If you are looking to spend about $300-$500 there is Sanitiaire or my new favorite:the Halo. It has great power AND a UV light under it that kills mites, fleas, etc in the carpet! It had a nation-wide price of $479. I am advertising it at Vet offices and Pediatrician offices... (BTW, I own a panasonic.  more