I love vim, but I think it would be excruciating without a full keyboard.
Wait, what?
Vi is actually the only editor that is bearable on a smartphone because most other editors depend on key-combinations (e.g. Control + X) that are painful to type on a touchscreen.
For vim you only need qwerty + escape and you're set.
I have been using Vim over ssh with my Nokia N900 not-so-smart-phone, and it works great compared to anything else I can think of. The phone has a physical qwerty keyboard but it does not have all the non-alphabetic keys you'd want and esc, ctrl and some other keys are accessed via touchscreen.
I have made some key mappings in Vim to get my non-US native keyboards keys that are normally not used in coding do something meaningful. I have ö and ä mapped to curly/square brackets, å is another escape and 0 and + (next to each other on the number row) are home and end. This makes it pretty convenient to write code on a qwerty keyboard and it also works nicely with a laggy phone internet connection over ssh.
I had a N900 and used to write lots of code in nano. It had python, ruby and PHP and was a great tool for quickly coding ideas or scraping and grepping web APIs. It ran vi and emacs too but I never really used them.
Now I have an Android device that's 5x faster and 10 more usable as a phone but I've only written about 10 lines of code in total on it's virtual keyboard. Hoping my next phone combines the best of both worlds.
My last three phones have had qwerty keyboards. The Nokia E90, a G1 and now a HTC Desire Z. Typing on them is so much easier than using a touch screen. I regularly tap out emails and use ssh and vi on mine.
