firstly let me say this is a really good machine. Far better than the Vax cleaner we had previously, and just as well featured. Compared to the vax it is better at cleaning, cheaper, much lighter and manouverable, easier to use and easier to clean with it's one tank design, with all the tools built in rather than constantly falling off the back and getting lost as with the vax. I was surprised at how effectively the bissell is able to clean and dry the carpets given its much lighter weight than the old vax machine we had. The vax had a built in detergent tank as well as a clean water tank, so you would think this would be good, but no, the vax detergent would thicken with time and clog the pipe that took the detergent to the spray, so often no detergent would come out. The vax was very heavy (especially when filled with water) and unwieldy, in fact it was so heavy that it's plastic handle broke due to the weight of the machine.
So overall the bissell beats the vax on every aspect, plus we only paid about £100 for the bissell where as the vax was over £150. If you need one of these machines (and we do with two small children constantly spilling stuff everywhere) then I can recommend it.
Negative points - seems to spray fluid to the side which is not sucked up on the same pass, but this is easy to fix by overlapping your tracks on the carpet, I think this is because the bissell has an edge to edge cleaning design with small brushes mounted to the side.
Hope this helps...