Although I cannot speak from personal experience, I have several friends that bought the Dyson upright and either thought it was a waste of money for what they got or hated it altogether!
When I bought a new vacuum about a 1 1/2 ago, I referred to the Consumer Reports article on vacuums. I ended up with a canister from Sears, a Kenmore model. Although it does take a little getting use to (like having the canister follow you around instead of in front of you as you vacuum), I really like it now. It is great on stairs, has a telescoping handle to reach high places, a button for an automatic cord rewind (no more rolling up the cord myself! YEAH!), a POWERED hand attachment for the stairs (must have the powered one, not the air driven one), hand controls on the handle, etc. One of the things I like most is that I can get under low places (like the bed & coffee tables) and completely vacuum since there is no canister to worry about getting in the way on the upright. Now I will say, if vacuuming with one-hand is a must, then a canister is not for you, stick with the uprights as you will need both hands since you will have to pull the canister along at times.
If you have the opportunity to try the vacuum before buying it, DO SO! Sears has a place set up and I think Best Buy does too. Make sure you don’t stick to the small patch they give you to try it out but instead moving around corners as you would do at home.