China Mieville does it again: an excellent book! This may be the best I've read from him yet (or best ever), though at the moment I can't decide if I like it more than [b:The City & The City|4703581|The City and the City|China Miéville|http://photo.goodreads.com/books/1320475957s/4703581.jpg|4767909].
The first ~third of the book is absolutely awesome. It's classic sci-fi like something you would expect from Asimov or Clarke.
The next ~third drags a bit, but only because the focus shifts a bit from being about the concepts to being about the plot/characters.
The final ~third is great and shines new light on that middle third that makes it quite exciting.
The ending is quite satisfying and the story overall doesn't feel as dark as some of his other works (I'm looking at you, [b:Perdido Street Station|68494|Perdido Street Station (New Crobuzon, #1)|China Miéville|http://photo.goodreads.com/books/1327891688s/68494.jpg|3221410]).
I love the way he expresses the Hosts' Language. It looks easy to pronounce, but is, in fact, impossible to do so- a truly alien way of speaking.
My only regret is that we didn't see more of the immer. I would love to read other books set in this universe.

I would recommend this book to fans of aliens, space travel, language, and/or sociology/politics. I would not be surprised to see this book nominated for (and winning) awards this year.

Update (4/19/12): after the Hugo nomination I decided to re-read the book. Here are my thoughts: strakul.blogspot.com/2012/04/book-review-embassytown-by-china.html