I have two - I modified the first, the second is still unbuilt (it came in one of the Mantic Crazy Boxes).
It comes with a selection of weapons and two different pilots - and a transparent dome over the cockpit, which includes a simple control panel. It also includes 5 tiny troops - just about 10mm scale - as victims of the shrink ray, one of the weapn options.
The plastic quality is good - not resin, restic or bendy stuff but good old traditional injection moulding plastic - or at least, that's what it looks and feels like. Very little if any flash, assembles easily, does not need pinning. My only gripe was that some of the parts come apparently already assembled and not easy to split from each other, and they have gaps which need seeing to - watchout for the arms and torso, mainly. The legs also seem joined and the joints have a raised ridge which should be removed. The plastic can be cut, drilled etc. easily.
The plastic is grey-silvery in colour, spray undercoat adhered directly with no problem.
No instructions for assembly, but after one or two dry runs all fell together easily.
It's quite tall - about 17-18cm (I modified mine slightly, hence the uncertainty). Long legged and a bit thicker at the top, it's a nice model. You can replace the Martian pilot with a human (or other) seated figure quite easily, and I chose a dark translucent dome instead of the one provided as I wanted an automaton instead of a piloted vehicle.
I'd recommend it - besides the original use it can find a home in sci-fi, supers, post-1950s pulp, PA easily. If you're good at adding rivets, it can be used for VSF, especially if the cylindrical backpack tank for one of the weapons is converted into a boiler.