Bike fit / correct riding position

You will gain from aerodynamics and you will gain from not having to use your upper body to support yourself. For long, solo rides, they're great. Braking and being nimble through any kind of town or traffic is not so good.

Ride near roadie types in a bunch though and expect to be left on the front or dropped and left for dead :)

I'm thinking for 6 hour + rides. My standard road bars will be there if the road gets technical. In fact, TBH, I was thinking of it as an additional position, more than a main one.

I fully intend to wheelsuck every single meter of the way.