So... This is an odd one for me. As a follow up to Prime, it's awful. It completely changes that more mature tone that series held, and completely changed almost everything else technical about it: the animation has admittedly a nice cel-shaded look, but the framerate is so damn choppy, at times it's hard to really enjoy it. The characters aren't all bad, but it's clear a lot of their personality was dumbed down for a younger demographic. And worst of all, it completely threw out the meaning behind (spoiler alert for those who haven't watched prime) optimus' sacrifice at the end of the movie finale.
But on its own, it's actually not that bad. Again, the colors in this show are AMAZING and easily the best part about it. The characters, although pretty simple, are still a lot of fun at times. And as for the story, aside from the return of Optimus, is actually pretty neat and continues that of Prime's very well. The action is also pretty fun, even if it would be a whole lot better without the frame rate issue.
Overall, I'd give this show around a 6/10. It's a birthday of a guilty pleasure of mine. As much as I like a lot of the steps they took forward in this series, it still feels like they took about just as many back.