Battery operated power tools have been around for quite a while. I know many construction workers have switched to battery operated power tools. For me, personally, I have been making the switch to battery operated power tools where it makes sense. I still use some corded power tools in my daily routine.
What I am gradually doing is switching the tools that I use the most to battery versions. I have used a Ridgid Palm Router for years. It is a very nice tool, but not having to deal with the cord would be a real plus. So, I just bought this Milwaukee Compact Router:

This is a small Palm Router primarily used for adding smaller profiles to edges of boards. It fits in your hand. I use this type of router fairly frequently. It will be enjoyable to use one without a cord. It just gives you so much more freedom of movement.
At this point, my battery hand tools consist of a Porter Cable brad nailer, Ridgid Crown Stapler, Milwaukee Random Orbital Sander, Works Tire Pump and several drills and drill drivers.
There is one drawback with battery operated power tools. I do not believe battery tools are quite as powerful as corded ones. For that reason, I keep a few corded tools around in case I really do need more power.
Battery operated power tools are a real plus when working on various projects. They have become the preferred power tool solution.
Doug