He thinks it's the greatest and actually WANTS to go in it!
I had the same thoughts and worries as you. See Harley is a "hopper" and likes to show off sometimes but he has NEVER toppled his xpen.. I've been ever so impressed! It has a lot to do w/ the -Eight corner stabilizers (black plastic pieces that can be used as floor protectors or to keep the pen in the octagonal configuration). It keeps them locked and keeps it from tipping. I've never used a top for mine but bet it would be a fine addition. I got mine from petsmart and it's been by far my best investment.. hehe besides Harley of course! Plus it's pretty inexpensive.. Check it out..
http://www.petsmart.com/global/produ...=1130729540656