Ah, yes, the Hasbro Prototype. Not a lot to say about it, really. It would have been nice to have him back in the day, I suppose. Here's some pics:

If it is not possible for you to acquire the Hasbro Prototype, then perhaps you would be interested in getting the Bw Neo unicron model. Hehe...strike 2.

(Pic 2)

We pause for an intermission, as we get the Hard Hero statue of Unicron:

And now...perhaps you'd like the Armada version? Third time's the charm, and this unit saw mass production. At a 50$ price point, he's half of what you would have paid for fortmax back in '86.

If you're wondering, yes, there's a variation on him. :-) See the Armada page for details.

Energon Unicron is a recolored Armada version. It took them 17 years to make one, so they're going to re-release him right away?!