Personally, I am one of those people who prefers things to be true to the original. I watched transformers growing up (Generation 2, which was the original episodes with opening, scene transition changes), so I went into the original movie with SOME expectations.
I understand that you simply can't regurgitate a storyline, so I really don't mind some play with plot/characters. However, I really wanted to see megatron as a gun and I needed to see starscream shoot him. Sorry, I needed that, and instead I saw some jet with little interaction with starscream at all.
As for the second one, soundwave was a...helicopter? And no classic soundwave voice?
For what it was, I'd say it was a decent movie that dragged on. For transformers, I was utterly disappointed. Oh well.