I'll admit, I initially balked at the price tag for the various versions of the UNSC Cyclops - $15 USD seemed a tad hefty for what was essentially a Drop Pod with arms and legs. But for that $15 the Cyclops mold is on par with action figures in non-construction lines, and offers a bulk that pleases both kid and adult collectors. Ball-and-socket shoulders and hips, along with hinge-pin elbows, knees, and toes put a decent spring in the Cyclops's step, and the forearms and shoulders offer plenty of weapon mount points - just snap on or peg in your creation and go (the piledriver is a great example of this, and can be retooled with little trouble into a grenade launcher or whatever you fancy).
And of course, since it's a giant piloted robot, it needs a pilot, and the UNSC Marine included features the classic 12-point articulation of the Halo Micro Action Figure assortment, and a Suppressed SMG to ward off would-be joyriders.
Keep an eye on the price tag for the Desert Cyclops and all its buddies - they're a great way to bolster your UNSC forces on the cheap (what with Drop Pods still being a Covenant-dominated market in most retail regions) and coordinate well with other UNSC sets' paint schemes.