We just bought a new vac. Read a lot of reviews on lots of different brands. Dyson did not rate very well ... low points for suckiness, longevity, and cost. But I'd take one if it was a gift!
We settled for a Kenmore progressive. Have a ten year old one (the handle release pedal just broke, am going to fix it) of this brand. The new one is made of lighter plastic (cheaper feel, imo) and they got rid of features they shouldn't have (one touch button on handle to stop the beater bars, beater bars stop on own when upright, dirt sensor), only one hard bristle brush that is too short, hose isn't long enough to do stairs all the way up the stairs (I just attach the extra hose from the old vac, problem solved). On the plus side, the lighter weight makes it much easier to carry up and down the stairs, it isn't as wide as our old one so now I can fit it between chairs/end tables, sucks much better (could just be because it's new though) and I got done vacuuming in less time, light is uber bright, not quite as loud.
The thing is, they used to make stuff that lasted but wasn't necessarily as good/efficient as today's stuff ... which they make to break (planned obsolesce anyone?) so you have to replace it more often. Our old vac was $220-220; this newer model was only $130.
Let me know how you like the Dyson. I tried bagless once (insert dirty joke here) but didn't care for it.