commander: I like it, I've used sometimes, I think it's the most used option.
minimist: I didn't knew it but I also like it, really simple. I choose this one.
https://github.com/crcn/celeri: I like the MongoDb shell and it's inspired on it. Moreover it supports both the interactive mode and command line. It includes a lot of common helpers like history, progress bar, spinner, password input, confirmation, prompt. Too much for what we need.
Using commander.js or any other library, adds flexibility to parse arguments better than doing it by hand: https://github.com/tj/commander.js