Bottwink was fun, and I also liked the butler.
It's been a long time since I last read a detective story, and it was interesting to note how it changed my perceptions. My sense of where in the story arc I am was all jumbled up; often in other genres, finding the murderer is a catalyst for further plot development, often accelerating the pace. I found myself wondering how come we're after the halfway mark and we're still just puttering about, slowly exploring the circumstances (and then of course going oh, right).
Another thing I seem to have forgotten about the detective genre: that I'm not supposed to be able to figure the resolution out logically from the presented facts, because some crucial information is always withheld until the very end. I suddenly recalled it always irked me; and I still don't like it. But it's not that big a deal, either.
The length felt just right.