TriStar:
Panthera:
While TriStar is a good machine, the quality of newer units doesn't seem as high as the older ones. The canister motor is no longer Ametek/Lamb, wands are now plastic instead of chromed steel, and so it goes. The way to get a good TriStar is to buy an older one; they made the classic "pig" design up until about 1993. Those are in the price range mentioned here. There is one difficulty, though: the price of repair and replacement parts. A genuine hose lists for $160, the rug tool for around $95, a replacement power nozzle for over $300. It's a little like a used Volvo; the car can be had cheaply, but putting it back into the condition it should be in can be an expensive process. I have about $400 tied up in my TriStar CXL, which was actually not in bad shape when I got it (for under $100) and had the majority of its tools. But filling in what was missing was expensive; it's absolutely complete and like new now, but I wouldn't recommend the process of getting it that way to anyone who didn't prize a good vacuum cleaner. If you luck out like Greg did and find a complete one in good condition cheaply, that would be great, but those deals are pretty uncommon in my experience.
All that having been said, classic TriStars are GREAT vacuums. They have a quadruple filtration system (cloth bag, paper bag, motor filter and afterfilter). When dust goes in, almost none of it gets blown back out; you don't see dust again in an hour the way you do with many vacuums. They do not have that "dusty" smell in use that most vacs have. And they have enough power to suck the chrome off a trailer hitch.