A fun toy although it's not that impressive engineering-wise. The truck mode is extremely disappointing in that the robot limbs just fold back behind the torso and... that's pretty much it. You can clearly see the legs and arms (since they're only partially covered by the wings), it doesn't have the sculpted details you'd expect of a truck apart from the cab (and even that, it's not too realistic).
The robot mode is where Optimus is a lot of fun. Love the Star Saber (although the blue plastic used on the Japanese version is superior, the green here seems tacky and ugly) and the inbuilt wings. What I like is that although his arms and legs are hollow, they've sealed it so you don't actually see the hollowness. Like others have said, the grey plastic is softer than you'd want which is odd.
Overall, a fun toy but not the best Optimus.