After needing a new vacuum every 3 years or so, even when choosing mid-range brands, and having had a Dyson Ball Animal that repeatedly failed and had to be taken in for warranty repairs (and then having a replacement from Dyson themselves fail), we went with a Sebo Airbelt D4 Premium. It was that or a Miele, but I thought the Sebo would do better with dog fur. It's a fantastic vacuum and has handled everything thrown at it. When we first got it we had 3 German Shedders, I mean Shepherds ;-) and had to vacuum daily. We're down to one Shepherd and one Chihuahua mix, so these day we can go longer between vacuuming.
I'll add that I was uncertain about getting a bagged vacuum, but wow, does having a bag cut down the dust! When I bought my Sebo I did so through an acquaintance I'd known for many years, whom I'd done business with for other natural/green products, and she was willing to give me a good deal, especially on accessories and filter bags. Buying the bags by the case saves a lot of money.