Bought this for an 19:month old.  He thoroughly enjoys it.

The install took about 1 hour to setup all the pieces and parts (probably 50 bags of parts) and four hours to build.  

The parts were all well documented.  

The instructions for the most part were clear.  I messed up on he placement of one of the fort legs and ended up having to drill two holes because I put it in upside down and had rounded the screws trying to get them off.

Great product.