I've had an upright Dyson (we had two Labs!) "pet hair model" for a few years, and I *LOVE* it!!! I was a bit nervous about the price, too, but they advertised that their machines don't lose suction, and after having like 4 vacuums in not that many years (we don't abuse them either, they just seem to lose suction quickly), I decided that it would be cheaper in the long run to get a vacuum I didn't have to replace very often.
For what it's worth, I feel that it's worth the money. The features I like best are that it doesn't lose suction, and NO VACUUM BAGS!!!
(because it seems you're always running out of vacuum bags at the most inopportune times, doesn't it? And they are pricey, and inconvenient to locate to purchase)