Forgive me if this is a little odd, I haven't re-read the series in a while.
The series is funny, the characters are good and there's some really good moments, both for humor, mystery, horror and a little bit of romance. In general if you don't like the first volume you probably won't like the rest of the series, the tone is fairly constant.
The series ends in a statisfying way, though and I appreciate that.
All in all it's not a great series, but a good one. Worth a read.