MacVim
Used by 24 peoplegithub.com ↗

“To get a sense of what vim was like, I switched last year (MacVim).”
Matt Might Interview, CS Professor (University of Utah) · via Uses This 

“I'm currently moving to MacVim for writing code, and after an initial learning curve, I'm really liking it.”
Tom Armitage Interview, Game designer, technologist (Hide and Seek) · via Uses This 
“MacVim's not far behind, which I use for both development and any random writing.”
Ben Kamens Interview, Lead developer (The Khan Academy) · via Uses This