I have been using the Hoover Wind Tunnel for over 10 years and like it a lot. I recently got a Neato robotic vacuum, and I love it! It's so nice to let it do the work, even though I have to carry it upstairs when I want it work up there. I know it doesn't do as good a job as I would with the Hoover, but I'm not complaining, and neither is the Neato.
Prism - I bought a Miele about 15 years ago and was extremely disappointed. It never did work very well, and I left it behind when we moved. I was so disappointed, because the reviews for it were really good.