I loved this! Lots of the great characters from the original, minus the annoying and cheesy human characters. I loved the darker tone!
It would have been nice to see a bit more transforming, but at the same time, they're on their own planet so they wouldn't have as much of a need to be in disguise.
A lot of reviews have lamented the voice acting, I felt it was decent. It was great that Starscream sounded the same, but unfortunately, many didn't sound quite the same. I must admit, at the start I did think that Optimus sounded like Peter Cullen but as it progressed, not so much.
I've not seen any of the series after G1, so can't comment on them, but I feel this does the franchise justice.