S2 - better performer, more reliable propulsion (inboard)
Catalina - "chevy malibu of the sea" - lots of them around - is the headroom really that much better? Easier eventual resale perhaps
Where are you sailing? If waves are likely the outboard may be problematic from time to time.
1984 Fast/Nicholson 345 "FastForward"
".. there is much you could do at sea with common sense.. and very little you could do without it.."
Capt G E Ericson (from "The Cruel Sea" by Nicholas Monsarrat)