We have used this exercise pen daily and it has served us well. However, it is not a perfect product.
Well-built and strong.
Door stays closed if you latch it completely (there are three catches for the latch, and sometimes you only hit one or two).
Easy to walk in because it is open on top, not just a portal door.
Shape can change
Needs to be tied down to stay in place.
Latch takes two hands sometimes to catch on all three spots.
bottom wire lays flat on ground so if dog has an accident, it gets on the bottom of the pen (would prefer it to stand on feet so less surface in contact with the floor)
Don't get this if your dog is already a young adult and hasn't been contained in a similar sort of pen. Here's why: We got this before our pup arrived so she has grown up believing the walls keep her in. So, even though she is now strong enough and tall enough to jump it or knock it over, she doesn't. I am pretty sure, if we got this for her as an adult, it would not contain her.
If you have guinea pigs (as I do also), this sort of thing would work well on grass, although you don't need walls this tall to contain them... maybe to keep other creatures out.
I hope this review has helped you.