Initially, I was put off by the promise of period vernacular, but the language did not go overboard into fusty or overblown ren-faire-isms or "speaking forsoothly" for its own sake.
The characters are well developed and likable, the town is easily understood, and the circumstances are well planned.
The mysteries themselves are outlandish but not unacceptably so.
There is a little too much "deus ex Dobby" for my tastes, though the threat of supernatural is soon understood to be a fashion of the time, rather than a step into fantasy on the author's part.
I am most disappointed by a lack of "wrapping up" of the series, the final book turns out to be the first written. While the ending of the series in the middle of our characters' stories is understandable in context of the times, there's a sense of being left dangling.
All in all, Frobishers was written first, you might wish to read it first. Don't expect a nice series closer, it looks like there won't be one.
They are a pleasant pastime, best if you are a faithful Elizabethan, but pretty shallow.