I recently tried switching from Grunt to Gulp and was expecting to see improvements in build times, but my builds actually wound up taking about 2x as long (on an ssd). Maybe I was doing something wrong, I don't know, but it was pretty disheartening. Here is my Gruntfile in case anyone cares: http://hastebin.com/wezizasiye.js
If build time is a big concern, I'd suggest Brunch. It starts out fast and it caches previously built assets so that subsequent builds are incremental.
this post encapsulates why development with js can be a nightmare. you start with grunt because that's the cool one, then everyone shifts to the new cool one -gulp- but oh wait, if you are concerned about build time, you need to be using this other new hotness.
