Compared with the Drone Attack, this Drone has less armor n' firepower, however, and due to his compact size and relatively low weight, the Assault Drone could be faster and dangerous at urban ops.
Speaking about the set itself, I think that this is the best Drone set to date. The design of the Drone is based on drones of CoD MW3 and I like more this MC version. The helmet of the soldier is a rare piece, so yes, it is good for collectors to have this one. And finally, in spite of the size of the Diorama, it manages to capture the essence of urban combat.
By the way, the machine gun isn't a rotating one as the one on the UVG Drone. This Assault Drone has a single fixed barrel machine gun that also can be toggled to manual fire from behind, assisted by an Ironsight mounted on the tip of the barrel which is also a very cool feature.