The Mandalorians feature in The Clone Wars cartoon series, and they have a strong storyline in season 2. This set comprises of four Mandalorian troopers, along with assorted weaponry and a speeder bike.
My 6 year old son had no problems with the build, and the Mandalorians are currently dug in behind Clone lines making frequent attacks on the unsuspecting army. He really enjoys playing with the weaponry, particularly the turret and heavy repeater gun. The speeder he is not that impressed with, and hasn't been played with since the build. There's nothing wrong with it, but it doesn't have any weapons of any note and so has been rather cast aside in favour of the turret, etc.
We hope to see Lego release a more exciting Mandalorian vehicle, but until then he is quite happy ambushing poor unsuspecting Jedi!!