Hi Mark,
Well, here's my two-bits...
It depends what you want to achieve, and what is taken as a 'given.'
I think the choice of the right boat for your purpose is more important than the specifics of the rig. If you've already settled on the boat, no variety of junk rig will make her comfortably do what she isn't suited to.
It's like rowing. You can row a 7' pram as hard as you want, and go no faster.
The junk rig is perfect for moderate goals.
Cheers,
Kurt