Can anyone recommend a really good hoover for getting dog hair from carpets please?

I am so fed up, tried Henry, Dyson Animal hoovers, but am very dissapointed with them, they pick up surface hair ok, but to get those worn into carpet I have to scrub with the nozzles which takes forever as you can imagine! Does anyone have a really good hoover that picks up long dog hairs (have 2 very hairy collie crosses!) without taking forever?! Thanks in advance!