I got my Uggs today and I have to say, I'm much more impressed with the quality of the ultra boots I got last week from
http://www.kiwi-sheepskins.com.
The shearling is far more plush in the kiwi boot, the construction feels sturdier, and the sole of the kiwi boot is much more rugged (granted, the Uggs are essentials, not ultras).
If you're in the market for some shearling boots, you should really consider saving yourself some money and going for the less expensive boots. I like them better. (Just be absolutely certain you order the right size)
Anyway, there's my comparative analysis.