Murder at the Vicarage was the very first Christie I ever read and I fell in love with her writing and the cosy murder mystery genre because of this book. Yet it's not my favourite of her extensive ouvre. Here's why:
1. Almost all the males are ineffective. Inspector Slakk is rather obnoxiusly so. 
2. Miss Marple comes across as very feathery and I hate how she's always apologising.

The mystery itself was good and the use of all the village biddies to introduce red herrings was clever and thematic. 

I will say that I enjoyed this more than Mr Osman's debut popular seniors' murder mystery and preferred Jane to Elizabeth.