Have to second dysonman's recommendation
I now have two Riccars--one is a Supralite 4 (purchased new,) and the other one is a 1500P, purchased on craigslist for $85. I think that the genuine Riccar HEPA bags are what enhances the performance of both machines. I prefer the Supralite's performance on high traffic areas and use it for daily pickups of beagle hair, dog biscuit crumbs, and husband-eating-in-living-room crumbs, and use the 1500 P for above-floor dusting (including the dratted 1980's popcorn ceiling, which is nothing but a haven for cobwebs,) and getting into corners.
They are both easy to use and don't kill my back (I had lumbar fusion surgery in December.) Both of them were purchased after numerous trips to various vacuum dealers and test driving everything I could find, with the exception of Kirbys, which I was convinced would put me back on an operating table because of the weight. One dealer wouldn't even let me try it when I told him I had a bad back.
I can't sing the praises of Tacony's machines any louder, and no, I don't work for them. I'm not a vacuum technician, just a housewife, but as near as I can tell, about the only difference between comparative models of Simplicity and Riccar is the color scheme for each line. The Riccar dealer turned out to be the older brother of a friend of mine, and therefore got the sale for the Supralite. The 1500 P was found on craigslist, to my great delight it was in excellent condition (brushes good, no weird noises, no hose clogging, and no dust in the dirtbag chamber.) Just a few cosmetic scuffs which buffed out with Pledge and a microfiber cleaning cloth.
But get the real HEPA bags. The price difference isn't all that much, they do have a pretty good capacity (even at 2/3 full, which is when I change them,) and it really makes a difference in what you're breathing around here!