I have a Kirby. It does a great job, buti agree with the comment that it's a bit of a pain that you can't get into nooks and crannies without the hose. Mind you, if it isn't doing the edges that's usually a sign that the belt isn't engaged properly, or needs replacing.
If you honestly use all it's other functions then it's worth the money - I don't. It's also VERY heavy, so if you have to carry it upstairs think carefully about how strong you are and what state your back is in.
If you're all on one floor, have lots of carpet, and/or have any allergy sufferers in the house (eg dust mite or pollen) then its well worth the money. If you have a lot of hard floors, don't think you'll bother to use the extra functions or think you'll struggle with stairs, then don't do it would be my recommendation. Are the Vorwerk vacuums in Australia (or wherever you are)? If so, perhaps they're a similar price? I hear great things about them, and apparently one of their features is being very light.