I was hesistant to buy something like this because I could just see the fall/injury risk. I have a 3 year old boy and 1.5 year old girl. This is the perfect structure for them! It is a great height for my son - not too tall for him to be really hurt if he did happen to fall. For my daughter, the bottom poles are too tall for her to climb onto, but she loves crawling through to the inside.
As for BUILDING it, pay very, very close attention to the details or you could spend twice as long building it like my husband and I did. If you pay attention, it is very easy. There is also a tool in the kit to help take apart some of the poles if needed, so that's a plus.
It doesn't, however, come with the stakes to secure to the ground. It has instructions on how to sucure it but it does not come with the actual stakes, which can cause a tip-hazard if not installed.