I play both electric and acoustic. I find myself playing the acoustic more, mainly because I like the mellow sound and the convenience. You can take an acoustic anywhere. You can practice anywhere, at work during lunch, in a park, jam in a parking lot, anywhere! You don’t have to plug it into anything. Of course, most of the music I write and play is Americana, Folk, Bluegrass, Old Country, etc.
As far as which to learn on, it’s definitely the acoustic. The acoustic will strengthen your fingers and build callous much quicker. Of course, if you have both electric and acoustic guitars now, play both, but the acoustic will improve your mechanics much quicker and better.
Good luck!