According to http://vacuumcleanersreviewed.co.uk and other review sites Dyson and Miele (German manufacturer - expensive) has no match. Personally I believe Vax performs superbly, and it costs like 3 times less than Dyson.
roomba. best thing ever. i just bought the pet version, just wonderful. it doesn’t get as hairy as the non-pet version i bought 5 years ago.
use it nearly every day, love that it gets under furniture.
We had a Dyson. It was good. We then got a Miele, and it’s very good.
I’ve had a cheap ($60) Hoover bagless for a few months and I love it. The motor is so strong, it’s almost self-propelled. It gets close to the baseboards and the edge of the couch (which is too heavy to move). The upholstery attachment works great too.
Sadie sheds like crazy, invisible hair that only the Hoover can see.
I also have a Dyson Digital Slim (cordless), but I only use the handheld attachment. It’s perfect for carpeted stairs.
Dyson and others are not universally good appliances within their product lines. Some models get rave reviews, others get nothing but hate. Do your homework before buying a particular model of any brand name.