Bought these boots to wear outside at an amusement park in 35-50 degree weather.  Wore them ALL day (9 hours).  They were very, very comfortable.  One negative was that as soon as they arrived, they began to shed, although not terribly much.  Second negative was that the shearling does not line the footbed of this boot.  ALthough I took the lining from my Uggs and used that and that worked out just fine.  As for the size, I was told by the manufacturer to order a size up since I normally wear a 6.5.  They were much too big.  I think a size 6 would have been better but I ended up keeping the boots and wearing two pairs of socks with them and as I said, they kept my feet very toasty - even when I was in temperature down to 35 for at least 3 hours.  I tend to wear socks even with my Ugg boots so having them run a little big was probably a good thing for me.  If you don't want to wear socks at all though and you are in between sizes, I would not recommend you go up in size.  By the way, I think these are much cuter than the similar looking Ugg boots, just as warm and definitely more comfortable.  I would most definitely recommend these boots.