I bought this for an 8 week old lab/saint bernard puppy. The purpose of the playpen is to keep my puppy safe while introducing him to my resident cat. The rest of the time, the playpen will be setup as a den area for the puppy to rest and keep toys. I'll keep the doors open. Speaking about doors, there are 2 openings with zippered flaps. I ordered Large and it provides sufficient space. The setup took a couple of seconds. Take out, unfold, done. The only thing I don't like is there is an elastic strap used to wrap around the playpen to keep it folded. The strap is attached to the playpen on the outside. Since my puppy will have the run of the room, he will be able to get to the strap. I will have to cut it off to make sure my puppy doesn't get stuck in it when I'm not there to supervise. A detached strap would be better but this issue is not significant to take away a star. 

Pros: functional and attractive design, easy setup, light-weight 
Cons: attached strap