I have been a pretty big fan of the Transformers film series. In 2007 I called the first movie the best of the year, and I loved the second movie even though the rest of the world (at least critically) seemed to despise it.
So I went into seeing the third movie with a bit of hesitation: I was wary about a possible token incorporation of 3D (as with many other recent movies), and of the departure of Megan Fox from the series.
I came out of seeing the latest instalment very happy, if but a little exhausted. The movie was about 20 minutes too long for my liking; a lot of the third quarter of the movie didn't seem that necessary to me. The 3D and the special effects in general were nothing short of spectacular. It's easily the best 3D movie i've seen since Avatar: it was very immersive without having any token scenes that I can think of.
Regarding the whole Megan Fox issue: they pretty much wrote her out in one throwaway line near the start of the movie, and probably mentioned her only another two times during the rest. I didn't mind the way they handled it; other than for her looks i've never been much of a fan of Megan Fox, with all the tattoos etc she's always seemed a little skanky to me.
Her replacement, Rosie Huntington-Whiteley, did a satisfactory job of fulfilling the role of eye-candy without too much else being required of her. I can't say I minded the swap, H-W's acting debut was at least as good as Fox's first Transformers movie, if not a little better.
Without spoiling, the plot was a little thin (which didn't surprise or disappoint me), but like with the recent X-Men movie, I loved the incorporation of the story into historical events like the 1969 Moon landing and the Chernobyl nuclear accident. The ending of the movie seemed to have a bit of finality to the storyline and the film-series in general. I wouldn't be surprised if it was the last movie of the series in it's current form, and i'd have to say that i'd be happy with it being finished off the way it is.
Definitely worth seeing :).