I accidentally started this series at book 4. I picked up the audiobook at my library without knowing it was part of a series. I loved that book and so have embarked on a Christmas holiday marathon of the other books in the series. 
 I imagine my reviews of them will be quite short. 
 The series opener, The Sweetness at the Bottom of the Pie, is terrific. Having already been introduced to Flavia in book 4, I was delighted to be back with her and her amateur sleuthing again (although she's so good at it, it's hardly fair to call her amateur). I think whether you like this series or not will hinge on how you feel about Flavia. You'll either love her or find her highly annoying. Personally, I can't get enough of her! 
 The mystery is well-handled and unravels at just the right pace to give you the chance to try to keep up with what's going on and make your own deductions. 
 I'd encourage any mystery/detective fiction fan to give this series a try.