We love this toy. It looks amazing, I love all the Japanese details. There's a lot of play value in this toy because the temple opens up and because the back of the temple is open (dollhouse style) and you get lots of minifigures. And the dragon is another toy in its own right and works really well with the temple. I can't resist setting up the dragon and triggering the opening mechanism!
My five year old can easily operate the opening mechanism - it's very well designed. You need to push both sides back at the same to close it, he can do this easily.
The Fire Temple stands up reasonably well to my five year old playing with it. But as with all Lego models, younger kids do need some supervision so they don't turn it into a pile of bricks ...
Older kids will be fine with the Fire Temple. The black roof pieces and their fire torches can get knocked off but are easy to put back on. The rest of the set stays together pretty well and can definitely be played with by the recommended age group 8-14.
Summary: This is an expensive Lego set, but there is a lot here. It's a great model to build and there's lots to play with.
If you want a similar toy for younger kids (perhaps to keep a younger child away from their big brother's Fire Temple) then try the Imaginext Samurai Castle.