Read the reviews and was a little skeptical, but thought for the price and size, Ill give it a shot.  Works perfectly for my needs.  I have to Guinea Pigs and they love it, so much more space than the hard plastic bottom ones you can get from the pet store.  I agree, feels flimsy but when you have it all together with the top latched on, its sturdier and works great.  The cage part velcros onto the outside of the canvas bottom so when change time comes just lift it off and go Im assuming but have only had it for the day so havent tried.  Big plus is I can use it outside in the summer without the canvas bottom so my piggies can feel the grass and soak up some rays without me buying a bigger fence right away.