I like that it's open source, so anyone can use it for free! The interface isn't very intuitive at first, but once you get used to it, its pretty easy to navigate around. It has some great features such as being able to access your files from anywhere in the world (as long as you have internet). You're not limited by file size or number of users.
There are many other options out there, but this one really does work well and doesn't require much setup time. We've been using code co-op since we started our startup and haven't had any issues yet. Its helped us keep track of all of our projects and tasks without having to worry about losing anything important.See full review