I have never sailed on either but I have been around a p16. They look fun but also they look heavy. Has he thought about a Hobie 16 or 17. Both those boats are pretty good boats and can be found cheap. The 16 catchs a bad rep about pitchpoling but in reality it isn't that bad. It is just weight sensitive which actually makes it a fun boat to sail because you movements matter.

There was talk on here about the 5.0 not to long ago, you might search for it. It is a pretty nice high performance boat.