Letterly sounded so cool that I bought three codes on the fly without trying the app. I gave one code each to my two sons as Christmas presents and kept two codes for myself. My sons and I immediately fell in love when we tried it. It's one of my top three AppSumo purchases ever!
I'm lovin' Letterly because it helps me stop my chronic overthinking, which leads to inaction. To combat inertia, I open Letterly on my iPhone, hit record, and talk to it. With its amazing rewrite options, one spoken rambling can be magically cleaned up or transformed into a journal entry, an FB post, a to-do list, etc.—outputs I wouldn't have produced if my thoughts had remained in my head.
I appreciate other users' feature requests and can only imagine how much greater Letterly will become with further development. That said, for what Letterly serves in my productivity toolbox, I'd give it five stars.