I've met both, Niven, twice, briefly. He was a grand story teller, but not really approachable.

Pournelle was always pleasant.

I had the opportunity to share a dinner with JP. I was on BIX, Byte Information Exchange, their "BBS" or "CompuServe"-ish service. And Jerry would occasionally sponsor small get togethers.

So there was about 8 of us just sharing dinner at a Chinese place in the Valley. It was a great time. The man can talk, to be sure. Sat right next to him.