I just saw this vid from BotCon with the Hasbro MP-10. Wow, I think the paitwork on the Hasbro is much better than the Takara!! Will definitely try to wait for the TRU Hasbro release!
There's definitely extra details, like the yellow tips on the small lights at the front. And the eyes seem to be a lighter blue so that you can clearly see them!! I like all that, and the Takara doesnt have that sort of detail!
https://www.youtube.com/watch?v=IAvDP-uBNvI
EDIT: Weird. I just checked a youtube video of the Gen 1 cartoon, and the Optimus did not have those yellow highlights at the top. So perhaps the Takara is actually more "cartoon-accurate". Either way, I might wait to see if I can actually get the Hasbro one shipped to Oz since it is so much cheaper!
EDIT2: Hmmm, after watching more youtube comparisons, I'm actually now leaning towards the Takara versions. They all seem to be more accurate to the cartoon than the Hasbro version (eg. the Rodimus MP-09 is much more accurate than the Hasbro version!). Damn the high price though!!!