I've never owned Uggs, so I can't compare the two, BUT I thought these were really great.  They are warm and super comfortable and way more quality than a lot of the cheap Target, Old Navy knock offs and they were a great deal for the $30 I paid for them.  Not sure I'd pay much more than $40-50 though, if they weren't on sale.  I wear a 9 or 9.5 and I bought and 8 and they fit really well with a little extra room but not a ton.  For my first pair of boots in this style I was really happy with them!