I've got a good bit of experience sailing Lagoons as well as Voyages. The Voyages are unreal! They move. We were making 12 knots in 18 knots down in the BVI on a Voyage 500.
The big differences in (big) cats in my opinion come down to two factors: clearance height (minimizing that slapping sound and wave-height clearance) and hull
shape ("V" vs. "U").
Lagoons have a moderate height and you still get the slap--or pounding, depending on the conditions. They also have a "U" shaped hull
. As a result, they're known for being more accommodating but lacking speed and pointing.
440's have a fixed keel
along with saildrives and decent-depth rudders, all help them point to the wind better than expected.
Could Forcynthia compete against a Gunboat? No. But I don't have that kind of money
We were close to buying
a Voyage 450 and decided against it because, while she would have been great to sail, we're going to be live aboards and need the headroom
. Plus, Voyages have the beds built into the body of the vessel rather than in the hulls--a downside of the "V" shaped hull. The Lagoon 440
has a (rounded) queen size bed
in the hull!
So, well you look at what we were going for, it fit our needs--husband, wife and daughter. If you're sailing around the world as a single
or a couple, you might look for something different (and even then need to make modifications).
Again--just my opinions.