Most of the slipper boots I've seen at the store were sort of cheap and the colors did not really appeal to me.  I received the Betsey Johnson boot-slippers as a gift.  First of all, I just love hot pink and black together so the colors were perfect.  The slipper boots are warm without making my feet sweat.  I did get a large, but I'm guessing they run a little bit big because I wear a size 9, and I was sort of sliding a little bit around inside the slipper when I put them on.  I had to tighten the little pull string in the back with the pom poms which helped a little bit.  The sole on these is pretty nice - I haven't slipped or slid and they almost have an actual shoe-like bottom which makes them better quality.  They come a little bit up over the calf.  Also, the inside is lined with the same super soft fur material that covers the outside.  They are very cushiony.  The only problem I had was with the little pom poms in the back - I guess I undid them somehow and they kept hitting the ground or hitting my leg.  I suggest not fooling with them - I had to tie them in a double knot.  I really wanted a pair of these and I'm glad I got the Betsey version.  I don't want to steer you wrong but I think a 9 might be like an 8 in these.  I'm keeping the large, but from time to time the bottom kind of turns over and I slide over the side of the bottom. Oh well, you could always return them for the correct size.  I know the price is kind of high, but similar ones I tried on at the store were just kind of bad quality.  All in all a great boot-slipper.