I’ve read all of them except Zero Hour, but mostly because I was such a RE fanatic, not because I liked them. Perry’s style of writing is nice sometimes, but too revealing; she tells you right away who is good and who is evil, who can be trusted and who is a traitor, taking away much of the suspense. Of course, as fans of the game, we’re already aware anyway, but I didn’t know Code Veronica by the time I read the corresponding book, and I found it quite boring because of that. Also, there are many unnecessarily long monologic passages about the evil guy going over his plans for the umpteenth time – I tend to skip them after a while.
Then there’s Perry’s unhealthy obsession with Rebecca. Not only does she appear in five of the seven books, but everyone keeps mentioning what an adorable, brilliant, skilled woman she is, especially for her young age… ugh! Don’t get me wrong, I like Rebecca, and I agree that she’s amazing, but does everyone need to constantly point that out? I think her actions speak for themselves. So generally, I don't really recommend these books, but to be fair, I reread Caliban Cove a few weeks ago, and after all it wasn't as bad as I had remembered it.
As for acquiring the books, which many seem to have problems with, perhaps this will help: I went to a book store, or any other store that had a book section, and ordered them there. This way it was quite easy to get them.