I'm getting ready to install a toilet flange on my basement concrete floor. I have a 3 inch pipe flush with the finished floor. I was told that I should not use an inside flange on a 3 inch pipe because it will restrict the flow too much. So I am planning to use an outside flange. I have chipped away the concrete and the flange will sit flat against the floor. My questions are, should I use a metal ring flange or solid plastic flange? Do I glue (using PVC glue) the flange to the pipe? Should I screw the flange to the floor with concrete screws. I have heard of outside compression flanges. Should I be using the compression flange instead of glueing? Any other tips would be welcome.

That 3" pipe, is it PVC or cast?

It is PVC

Since you have chipped away the concrete, cement the flange on using PVC Cement and a primer. A metal/PVC combo may not break but PVC on a concrete floor doesn't usually break either. The flange only holds the toilet flush, the toilet sits on the floor and the weight is borne by the floor. PVC flanges will break when the toilet isn't tight and rocks back and forth.