I recently used them to go from copper to cpvc (i hate soldering) and they worked great. No tools to install at all.
I don't know where they are able to be installed (codes and whatnot) but they worked for me.
I use fittings similar to those on machines I work on... I LOVE THEM!!! The fittings I use are for pneumatic lines or hydraulic lines. They definately won't leak, and are SUPER easy to install! Hope this helps.