Can't go wrong with either one.
We had a 328 with 275 Verados and after putting stock Merc Rev 4 with 25 pitch we ran 72 mph and 4000 rpm was 47-49 mph with 8.5 to 10 gph per engine.
Glasstream is a self bailing hull which we prefered.
With identical power It will always be faster than a Concept due to the steps.
Probably faster than a 31 Reggie boat.
More and more Glasstreams popping up everywhere. Seeing quite a few new ones in the Bahamas(Abacos).
We loved ours and we speak from experience.
BIG BIG BANG for the buck!!