My 55LB Pit mix loves this bed. I could barely get it full assembled before she was diving face first into it. She sleeps on her belly, on her side, and on her back all while feeling totally comfortable. She used to follow me around the house all the time, but now she feels comfortable watching my movements from afar in the comfort of her Casper dog mattress. 

Would 100% recommend to a medium sized dog. Easy unzip for washing!