I got the larger size for our 90lb lab, and he loves it.  He was previously on a round bed that he would start out ok on, but then be 1/2 hanging off by morning.  Now he's all sprawled out and seems to like that little extra edge for his head to rest on.  Our other 65lb rescue keeps trying to claim it...May have to get a 2nd one.  It does take up ALOT of space...but oh well.  Furry kids vs. empty floor space .