Finished Old Man's War yesterday and must say it was pretty good, it felt a bit like Starship Troopers the movie and ended pretty quickly though. Will most likley read the other 2. I give it (****) stars.
I gave it the same biodroid and I gave the second 3 and the third 4. I think the main reason I marked the second one down a bit was that it someone seemed more about the fighting than the characters, even though it offered if anything a better opportunity to dig deep into characters.
Vertigo - I must say it's a lot lighter than say Neal Asher or Iain M Banks. I prefer Neal as I have tried to read Banks and couldn't get through Consider Phlebas, but JS is not bad just too whimsical. From what I see he doesn't take himself seriously and it shows. I admit I like the wit but it's not the be all and end all of a book, to me it has it's time and place. The world building was ok, nothing impressive, and perhaps lacking throughout the book.
I think I would agree with you biodroid. An altogether lighter read than the likes of Banks or Asher. Though I would say the second and third books are a bit darker. The wit is still there but the overall feel is a bit more threatening.
It's actually something that annoys me rather. Most military SF I find tends to be somehow less consequential. Even taking Asher, I would say that Prador Moon is his closest to military SF and I would also consider it one of his lighter less consequential books (possibly along with Gridlinked). Still excellent but less weighty than most of his later books. I don't see why that should be the case but I've just done a quick scan of all the books I have clasified as Military SF in my database and I would say they all tend to fall into the lighter end of my reading. I'm also afraid that for me that judgement includes Haldeman's books.
I think if you tried Scalzi's The Android's Dream you will find the wit is still very much there and the basic premise is deliberately a bit silly but the book is somehow much darker; the humour more satirical and cynical in nature perhaps.