Awesome group of books. I've got several I own at home. There's no real stinkers per say however one of the most recent ones really takes some tremendous liberties with the size, capabilities, and sapience of a Mk. XX. You've got several novel length books as well as some short story anthologies.
Road to Damascus, that's the new one. Yeah, avoid it until you're much more grounded in the Bolo universe. It's not a horrible book but it's far from the best or most technically accurate of the series.
I'll recommend a few titles when I get home and can look over my book shelf. This series doesn't really do much with titles.