I'd been trying to get hold of this book for some time and, eventually, ended up getting a second-hand copy. I've read it over the last week and have just put the book down after reading the last 150-or so pages.
As far as characterisations go, there seems, to me, to be a pretty thin veneer on most people in the book - there are quite a lot so it would be too much to ask to develop them all... however, I don't even feel as though Blaine was made clear to me. Sally, on the other hand, did my nut in - as well as the Chief Scientist - they just annoyed me frankly - with their pre-formed ideas being used repeatedly in the book to offset the views of common-sense... so, the book has some realism there - you'll never have large groups of people who are all sensible - so truth in that.
With regards to action... it is spread out, with just about the right levels of suspense and intrigue and guesswork required on your part as you progress through the book. When the action does come you are dragged along with it and are able to visualise it well and care for the outcome.
I still can't really decide whether the Moties are just trying to get out of their "Cycles" and see expansion as a necessity, or whether they are hell-bent on conquest of the only other civilisation they have come across. There are parts of the book - where some of the main Motie characters are talking - when they appear extremely calculating and callous. The Moties, as aliens, are believable and actually quite worrying... faced with the moral dilemmas that are in the book I'd go for the easy option of quick, out-and-out, extermination of the blighters.
At times the book can be a little slow - with, seemingly, not much happening - however, these lulls might be storytelling means of building the reader up onto the crest of a up-coming wave of intrigue or action - of which there are plenty.
The final solution in the book was a bit of a surprise to me - I didn't see the story going that way - and obviously I've now started researching for the follow-on book - but I see that it has generally negative reviews on Amazon... I wonder if I really will bother trawling through it?
So, all-in-all, four stars for this... I had waited for such a long time to read it I might be guilty of allowing myself to be a tad disappointed.