Mr. Shhh
As a writer who loves his muscle description, I try to use other authors as examples and no one is a better example than Mr. Shhh, this guy is the dude that I based my Muscle Impossible stories after, he doesn't write much anymore, but when he was active, I enjoyed anything he ever put to paper.
Michele Roppo
Little Annie Ample... enough said.
Reaper00200
Another great writer who uses great muscle description in his stories. His characters have muscles everywhere, in every single nook and cranny on the female body, it is developed to the extreme. As a reader who loves this kind of freakishly extreme muscle, I love to see a new story from him whenever I can.
http://© Saradas.org/stories/monster-series/monster-doorway
Honorable mentions
GBM- Extreme muscle size and strength also favorite subjects of mine, I've tried in a couple stories to try and write a GBM style story, but I could never match the master.
fighterpilot909- yes, he's new and his writing is exclusive to forum saradas and the people who commissioned him, but he has had a great impact as far as using creative muscle descriptions and strength feats, and I very much can't wait to see what more he can come up with.
Beegboy/Uplifted/MBP/Spoonmaster- I very much like to see bigger boys and men overpowered and lifted and carried by much smaller girls and women, these four are perfect examples of that kind of story.