Just got back from the IMAX showing.
I won't get too much into it, but I feel they grabbed random things they liked from the mythology as per the comics, the cartoon, and the toys...little things they kind of put together. Can't really explain what I mean without going into "spoilers"...so I won't, not here and now, anyway.
Good action when you could tell what was going on. Still lots of blurry metal crunching action. It's been bragged that there are 40-some robots here, but there were MANY that showed up for maybe a minute. No joke. Like guys in the background, who would just kind of show up whenever. A few were killed moments after appearing, with less time than Bonecrusher in the first film.
I think all the people who are complaining about the crude humour need to lighten up. I always thought I was the first to cringe at such jokes, but it's seriously not a big deal, and I don't think any of it was quite as bad as "Sam's Happy Time" from the first one.
In closing, I think it's a bit better than the first, but could have been a lot better if more Transformers were actually named and given real screen time.