First of all I LOVE the Imaginex products (we have the bat cave, boat and construction vehicles.) I really think they are one of the most durable products for kids on the market today. I bought this for my son's 5th birthday and was a little nervous it would be too 'young' for him since he is really starting to get into smaller figures (lego, playmobile etc...) but WOW .... he loves it. It is his favorite gift and he plays with it every day.
It is HUGE and there are so many compartments and things for the 'guys' to do: Fly the planes, stand on the look out tower, go under to get ready to fight! It really encourages my son's imaination and creativity. It comes with 2 guys and 2 small planes that are good - but very simple. I bought one of the larger planes and that is a lot of fun and my son is able to have battles and fly them together. As some of the other reviewers suggested a big plane is a nice addition but not completely necessary.
The disks drive me nuts since they are flying all over the house but that is one of the best parts acording to my son:) My youngest son is 18 months and he plays with it too - puts the guys in the planes and flys them around the house etc. It is so sturdy that I know it will be around for him to use as well.
I see both boys playing with this for a number of years - definaely worth the $$ for the size and detail - actually surprised it does not sell for much more!