I'm in the same boat. Critics should never be listened to, ever. More often then not they go expecting to hate something and have the mantra of "ok, prove me wrong". That's just as bad as setting your expectations too high for something. I saw two critics give Last Chance Harvey Oscar worthy nods, when in reality, its the first movie to prove to me I really can doze off on a plane.
As for the movie, I really enjoyed it. It's exactly what I want out of a summer blockbuster. Big action and it was brought on a grand scale. It's a popcorn movie and made to be over the top. Plot was thin, but not much more than the first. If you loved the first one, you'll probably at least like the second. You'll see a lot more transformers and action in this one. Optimus's vagina transformed into man parts for this one and he was a beast.
Other than that, you'll hear from all three camps on the movie: (and this is not aimed at those above as much as at all the sheep in the world) those who hate Michael Bay because it's the "cool" thing to do on the internet, even though most of them couldn't name more than three movies by him, but continue to see every one of his 200+ million dollar profit machines, those who religiously follow what critics say because they are clearly professionals on what you as an individual like, and lastly those that will just give you an honest opinion. How you decipher which is which all depends on how long you listen to them. Watch the trailer, because like in most cases, what you see is what you'll get. Thin plot, lots of action, and a continuation of the first.