Orion Arm continues the Julian May tradition of creating worlds described with vibrant adjectives that make her worlds a feast for all five senses. Her prose is perhaps unmatched in science fiction, and it is a joy just to read her works to see how she puts together her sentences.
Orion Arm continues in the vein of sort of goofy, tongue-in-cheek action adventure and humorous cynicism from rough-around-the-edges protagonist Asa Frost. The plot thickens, becomes at once more serious and complex than in the first book. The first one was definitely more fun than adventure-- this book adds just a bit of suspense, making it more enjoyable. Much of the new tension comes from the shifting of emphasis from evil megacorprorations to a xenophobic alien race with ulterior designs on our galaxies-- it sets up the action for book 3.
All in all, I enjoyed this book a tad bit more than the first, but still rate this series slightly behind May's earlier works. Unlike Pliocene Exile Series, where I found myself admiring May for her ability to let us come to know even secondary and tertiary characters, this series' supporting characters were somewhat superficial. Oh, compared to most sci-fi, Ms. May's characters are all vivid and deep, but compared to her own unusually high standards-- this falls just a bit short. Still, entertaining, imaginative a good read.