I have been considering my options lately as to which task runner to use. I have always used grunt to handle task management and have been looking at gulp as many projects are leaning that way. I haven't pulled the trigger as I haven't found the need.
In my most recent projects, I have just been using npm scripts to do this. Today, while searching the usual google "grunt vs gulp" I ran across this post How to Use npm as a Build Tool and it caught my eye. He brings up some good arguments and I personally find the final output appealing. It is a little harder to read but there is so much going on in such just a few lines of code that you see a much bigger picture in a smaller amount of text. One additional benefit is there is less "magic" going on here. You understand what is happening and you can run any of these individual tasks directly from the command line.
I plan to take this approach for my next few projects and see how it goes. Not hard to switch back to grunt or gulp if the need arises.