I haven't read a lot of translated books, so to be honest there are a lot of grammar and phrasing that you could tell where not native English sounding. It could be a little distracting at times, but once you get into the flow of the story it's not too noticeable.
This was a fun book. Auntie Poldi is quite the character! I love mysteries and I love stories with a lot of character drama/character building and this story really fit the bill for all of that for me. It did take awhile to get to the murder and mystery bit. The intro did drag a bit... hearing all about Auntie Poldi's backstory and family and how she ended up on the house on the sea (even the house hunting experience itself)... but I can't complain too much since I do like character building. If you can get past the slow intro this book picks up and is a fun read!