Bought the smaller playpen to contain an older cat recording from surgery after wasting significantly more money on a Pack-n-Play. The pack-n-play was super bulky %26 so difficult to manage. Really wished that we had found this thing first!
The older cat did eventually chew a couple of small holes in the mesh window for the door flap. However, I think that if she hadn't been made aware of the fact that the door flap existed (if we had only used the top opening) it wouldn't have been a problem.
Bought the larger size to hold my rambunctious, year old, moose-sized, Savannah cat when we travel %26 she's unable to be left on a leash. It's so handy %26 ideal for traveling with a pet. Very lightweight yet sturdy, super convenient %26 easily stored just about anywhere. It folds almost completely flat %26 the way that it folds up makes it quite easy to configure in a smaller size/shape. Say you needed to confined a pet in the hatch of an suv while you're loading groceries in the vehicle %26 wanted to ensure the critter had enough space to move around while they waited for you to finish... fold in a couple of the sides (maybe stick some velcro on the panels to ensure it stays put) %26 you have a nice, inexpensive, spacious, collapsing kennel in an instant.
It's great for sunny days when my cat wants outside but maybe the lawn clippings haven't been cleaned up yet %26 so, the leash isn't necessarily the best idea. With this she can still be outside with us %26 safe.