Read that wonderful NSFW one shot about Shamiko and Momo so I decided to read the official manga too. It was awesome.
The ability for the author to plant little seeds that won't come back until late in the future consistenly amazed me (really hope that Momo or Shamiko getting their memories of the other erased and then brought back through the power of love ends up happening).
Momo is definitely my favorite character (not only of this story, but she's now one of my favorite characters in general), which ties to my one problem with the story: Why can't Momo find out she has sealed memories? I wish Mekato had given some sort of explanation for that. Still, I'm confident it's going to be dealt with, hopefully through kisses.
I also like how, despite growing stronger and more skillful, Shamiko is not becoming a complete expert in her powers.