I have a Dyson V8, but I still prefer to use my good old Miele bag vacuum cleaner with a - and this is crucial - Elras multi nozzle.
Yes, cordless is nice, but I find the Dyson's handheld part quite heavy and the constant button pressing is a totally unergonomic hand position for me. So I'm actually glad it only has 15 minutes of suction power, because by then my thumb falls off anyway.
And without a floor nozzle, nothing works (at least with my model). In other words, if I just hold the tube (without an attachment) somewhere, it doesn't even suck up cobwebs. With my Miele, it sucks in the cobwebs and also the paint from the wall :D