Why would anyone choose Grunt instead of Gulp as build system?
Honestly. I don't know. Maybe,... because they don't know gulp?
To be honest I started with grunt, too. Beacause some boilerplates used it, and it was the first build system I heard of. But gulp has a nicer and easier syntax and is way faster.
Sara Vogel
Lady JavaScript Programmer from Germany
If you had asked this question a year back, I would have said "Availability of more grunt plugins", but this doesn't hold true today. Gulp is better than Grunt in every aspect, but is more code driven. If you want to be configuration driven rather than code you are better off with Grunt.