I bought the largest size for my rabbit, but I've been using Midwest products for 30 years.  The cage is roomy and VERY sturd:  I have large dogs and I would trust it for them if they needed a crate.  It only takes a couple of minutes to unfold and fasten, and all fastenings, edges, corners, etc.  are smooth and sturdy.  I comes with a divider panel, so if you have a small, large breed puppy, you can adjust the size of the enclosure at it grows.    The extra large is pretty heavy but if you need this size, heavy means sturdy.  I don't trust my animals (dogs, cats, rabbits, etc) to anything less than MIdwest.  A superior crate in my opinion.