Forget suction power... many vacuums claim great suction, which I honestly could care less about. How well a vacuum lifts the dirt out of my carpet is the only reason I would buy a vacuum, or better yet; keeps (or makes) my carpet new is the most important thing. The Dyson Vacuum has incredible lifting power. I got the Dyson and then vacuumed my house for the last time with my old vacuum and then vacuumed again with the Dyson. I kid you not I dumped the Dyson out 4 times before I was done with the whole house. I vacuumed my house twice every day for the first week (first pass would net two dumps and the second would be ¼ full); I think foot traffic loosened the ground in dirt. By the end of the week my carpet (which I was about to replace, the reason I got it was to use on my new carpet) had lost years. A new carpet isn't cheap, so the investment in the Dyson literally paid for itself in a week.
I've had the Dyson now for five weeks and my carpet looks like it did 10 years ago. Now, I only vacuum once a week now and barely get a canister full of dirt.
Oddly enough when I first started using this vacuum on my floors I had a lot of stains (two kids and one dog and one cat) I was just about to have my carpet professionally cleaned (a last ditch effort to prevent a costly replacement). Now most of the stains have gone and those that remained I was able to take care of with carpet cleaners, Again another savings. The only filter on it is still clean and only sometimes I feel I can smell dust from it (the emissions claim). And that's only when I sweep bare floors (my garage) where people have dumped cigarette ashes on the ground. I think it may have a weakness in the attachment tool (its clumsy to reinstall), but that is still working fine. Bottom line is it's really my kids' job to vacuum and they love it. So if 11 and 13 year-olds can use it and my house looks (and smells) clean, Dyson must have done something right. I suggest you buy one now.