I'm going to echo the above, and say Wheeljack.

I may be biased, as he was one of the few G1 toys I had, but he was one of the most prominent Autobots in the series, often the source of inventions & new technologies.

He and Bumblebee were the first two Autobots on screen too in the initial scenes on Cybertron.

And the Masterpiece toy is pretty much universally regarded as amazing.