4 years ago, we received a phone call asking us to sit through a demo of a "home cleaning product", we were told that it would take 10 minutes, and we'd receive a free 3 day vacation.
The next day a young man showed up with a huge cardboard box. It took him 10 minutes just to get everything out of it, then another 5 minutes to put it all together. He said it was a tristar vacuum. He proceeded to suck up some sand from a container, then asked if our current vacuum was as good as the tristar, I told him yes, and said that I wanted to show him a demo of my own.
The BEST way to test any vacuum, is to hook it up to another vacuum (hose to hose), and turn both on, and see which one stops first.
I pulled out our Dyson, and hooked the hose up to the hose of the tristar, and turned both on. It took about 2 minutes for the tristar's motor to burn up. I have done the same thing to rainbow's, filterqueen's, hoovers, dirt devils, and I have always had the same results.
The tristar ($3000 + for a new one). Is too big, too complex, and has too many pieces to justify being bought, just like any rainbow, electrolux, or filterqueen vacuum's.
Dyson is the way to go, I've sprayed paint stripper on my walls, and then used my dyson to suck the old paint off after 10 minutes time.