I ordered the large for my 42lbs Border Collie and it’s smaller than I thought it would be. She fits as long as she’s curled up but barely fits if she stretches out. The sidewalls are nice and plush and the memory foam, in my opinion, is adequate. I did put another cushion on the bottom of the bed to make it more plush. Having said that, all that really matters is that my dog seems to really like it, she crawled into it immediately and has slept in it almost every night since receiving it.