I love them. I found the series something of a slow burn, though, and found the first one a pleasant enough read, but nothing more. I read the next few, and decided that although I'd enjoyed them, I couldn't be bothered to read any more. I returned to them some years later, and this time read further on in the series, and ended up loving them.

Each book broadens the scope of the world, and adds more secondary characters and ongoing plots. Characters grow and change. It's certainly a series that evolves as it goes on, rather than establishing a formula in book one and sticking to it. The author claims that the books can be read in any order, and there are passages in all the books that are very obviously there to explain relevant backstory to newbies, but I would strongly recommend reading them in order, if you decide to read on.