The author has created great characters and settings with this series, but I wish she would slow down and sharpen her story lines. Someone said they keep getting better ... I think the opposite. The plots seem to be getting looser and looser, with increasingly wild and improbable things happening.
On a positive note, her characters are very interesting. You want to catch the next episode just to hang out with them, the shop and the town with its constant stream of events. And, truly, her tea information, recipes and tea party tips are good resources.
I can see these becoming a television series or movies, but they would have to completely rewrite the "mystery" part. The stories just abound with plot holes and improbables. She also fails to wrap things up or tie up loose ends. One example in one book, a new assistant is hired. You get a little dialogue with her and then no further appearance or mention. Another one -- the lead character has a succession of boy friends, who are presented as great guys initially and all along, but there's not much mention or interaction with them. Then, suddenly, as the next one is introduced, the former one is portrayed as a bad guy with all sorts of quirks and/or is used for some wild story twist. Real sloppy stuff.
Oh well, people are snapping them up anyway, so why spend the time on the story, I guess. If you can just enjoy the venues, characters and charm of setting, you'll be good with these. By the way, books like this are always formulas (as many a popular TV series, etc). That's not the problem. Just reader discretion advised on story line - if you really try to follow it, high frustration factor awaits.