As someone who only reads a few mystery novels a year, I was overwhelmed to discover both Andrea Camilleri and Donna Leon at about the same time. Camilleri's Inspector Salvo Montalbano stories and Leon's Commissario Guido Brunetti novels are so good that I wanted to read them all and was delighted to find that both authors have written at least a dozen books each. Only five or six of Camilleri's have been translated into English from the original Italian so far, but more are on the way. And many of Leon's are out of print in the U.S., but perhaps that will change in the near future.
These are compelling mysteries that draw you right in and keep you hooked right up to the satisfying, if not always happy, conclusions. But that almost goes without saying. What keeps you coming back for more are the characters and the extras, in this case, the backdrops of Sicily and Venice.
Stephen Sartarelli's translations of the Camilleri books are marvelous. It isn't hard to translate a book, but it is difficult to do well. He strikes the perfect balance of translating most things, but turning to explanation when translating would destroy the mood. There are a few pages of explanations at the end of each book, describing pastas and exchange rates and cultural references. For instance, he translates education-impaired cop Catarella's rough speech into something Brooklyn-esque, but he explains Boghonghi the Dwarf, apparently a famous character to most Italians, but not to Americans. (Example of a bad translation -- I remember seeing a dubbed version of the French movie A Man and a Woman that completely destroyed the romantic mood when they replaced the Edith Piaf song playing on the car radio in the original version with a dubbed ragtime tune.)
I can't say which series is better, I tend to think that whichever I am reading at the moment is my favorite.