I use these fittings on all my air tools and I love them. In conjunction with a lightweight hose, my pneumatic tools are as easy to handle as a corded drill - or even easier since the tools are generally smaller. As Mel said, they're not great for really high-flow applications (not a problem for my shop). I use an air swivel on my rivet gun and squeezer, but I haven't found it necessary for any of my other tools.
Definitely I would suggest purchasing from Cleaveland Tool if you have the opportunity. For builders located in countries where the shipping would be prohibitive, I believe these are
Rectus 21 series fittings.