I have to be critical of this one.
Just considering the original toys: As the semi rig, Prime's original design was at least logical. He had the right number of wheels and the layout was close enough to realistic. This version does not impress me. While I'm sure the engineering is well done, the vehicle mode looks ridiculous. The sculptor should have worked from some photo references of real steam engines. Even the original Astrotrain toy was more convincing than this and that was a mass of compromises.
The ROBOT mode looks impressive, yes, but I need to see Transformers look good in both modes or the effect is lost.