Fractional vs. Masthead Rig
Ahh, see the difference an archetect makes in a discussion! I developed my "feelings" based on years of imperical experience, and Jeff is able to put it into nice technical terms.
Either way, 6 of one, half a dozen the other, I think we are saying basically the same thing.
Jeff has picked up on my more "racing" spin on a topic.
From a rating standpoint, the masthead rig gets the advantage of the unrated sail area. That is where my "faster on all points of sail" comment comes from. If you limit actual sail area, you will see that the fractional rig comes out on top. Once again, an example of designs being influenced by rule formulae.
I can assure you of a good deal of "pucker facter" involved when dealing with the masthead rigs outsized down wind sails when the wind pipes up! The fractional rigged boats greater reliance in mainsail power makes it a much more controlable rig in a blow. They also respond very nicely to tacking down wind as their speed potential off dead down wind is greater, along with the greater ease of gybing the smaller chute.
Also my thoughts regarding running backs/check stays is geared towards the ultra high performance realm. I use runners to stop the pumping of my bendy masthead rig when sea conditions require it. A well designed fractional rig gets by nicely with just a backstay, but you still have to handle the tension properly to effect mainsail shape.
Now that I think more on it, the baby-stay, vang, backstay, outhaul, cunningham dance I do on my boat every time the wind changes 2kts is a little more complex than just a simple backstay adustment. Maybe I sould go out and play more on other boats...