Jekyll and Hyde is very good, the central protagonist is the grandson of the RL Stevenson character.
Penny Dreadful didn't know what to do with itself, both Dorian Grey and Billie Piper's character could have been left out without affecting the plotline.
Honestly, the Billie Piper arc had great potential; where she was at the end of S2 was unexpected yet made sense.
My impression was that S3 would be entirely about her and Dorian Grey wreaking havoc, and the reason why I liked this idea was that the show started with her as an unassuming antagonist.