The opinions I've gathered all seem to center on the build quality. But something I've kind of picked up on is they're a very early "modern"
catamaran, that also happens to be very well built. Just my opinion, but look at a lot of the designs before then, Snowgoose, Hirondelle,
Catalac, Comanche, Iroquois, Heavenly Twins, etc they all look very dated, and to a certain extent are built to an older style. No tramps, low bridgedeck clearance, accommodations in the bridgedeck, etc. Put a 42 TPI next to one of those and it looks like a spaceship, put it next to a modern cat and it doesn't look totally out of place. I know FP was building more "modern" cats around the same time, and earlier, but I don't know about the build quality.
I'm no
catamaran historian, but that's just the opinion I've picked up. And full disclosure, I have a sweet spot for the 42 TPI, I would love one.