My personal policy was always to take as many jumpseaters as we could legally allow. I was a commuter and always appreciated others taking me.

That said, I usually found it more comfortable for the jumpseaters and the crew if we filled up the jumpseats in the back first. If one of those looking for a ride was a young enthusiastic Commuter Airline pilot who wanted to ride up front he was welcome (they sort of reminded me of myself when I was their age).

I only had one bad experience with a jumpseater in the cockpit. Upon arrival in MEM the j/s stood up and said, "I'm a Check Airman and I want to debrief this flight." (He should have said that when he got ON the airplane ... A-HOLE!*?