The Stopler mold was taken off of the hull of my previous boat, a Knowles 37 Express. Prior to buying my Knowles I looked at several Stoplers, and they are nice boats, no match for a cold molded Knowles, but nice boats.
Stopler didn't quite have the balance down on the boats he put the 450 c series Cummins in, and added forward spray rails that made the boat ride stiffer than a Knowles, and wetter. The Knowles I had ran beautifully, it was a fantastic sea boat for 37' and rode better than a Viking 50 for example. It was very economical, with a 30kts cruise at about 30gph, and a 24kts cruise at about 20gph with 6BTA 370hp Cummins. I suspect a Stopler with 370 Cummins would ride pretty darn well and be almost as fast and almost as economical as the stiffer, lighter, cold molded Knowles. Also, the Knowles was a fish raising machine, and we saw billfish behind the Knowles way out of proportion to most other boats (and it wasn't our incredible skill either!)
The cockpit on the Stopler is as large as on the Knowles, and that is a plus for sure. We had six on my Knowles frequently, but it was tight with six, as any mid size boat is going to be.
BTW, on my boat the beam was 12' 2" or so and the actual hull length was 37' 6"; since the Stopler mold was taken off of my boat I suspect the length and beam are identical. 3:1 length to beam is the traditional recipe for a great riding boat, and the Knowles and Stopler are very close to that. It sure worked for the Knowles. Also, both the Stoplers I ran and the Knowles handled extremely well.
I met Stopler at his plant somewhere near Palm Beach. I believe he used Kevlar in his lay up schedule - and my Knowles had a Kevlar layer or two on the exterior - and I think he used Divinicell foam coring, at least above the waterline. I wouldn't shy away from a Divinicell cored boat, or a cold molded boat either, and a survey will reveal any water intrusion in either. With Kevlar there won't be water intrusion. It took a truck full of hole saws to install a through hull transducer in the Knowles.
FYI, there is a '93 Knowles for sale that was recently repowered from 330 Cummins to 370 Cummins, and the boat looks to be in fine shape. The ask is $415k, which is a bit proud, imo. Here's a link: http://www.yachtworld.com/boats/1993.../United-States
This one isn't my old boat, my old boat is in the Honduras charter fishing for billfish. Here's a link, the changed it around some, but not much. The Release Helm chair is gone and the boat used to be sea foam rather than white: http://www.a-fin-ity.com/A-Fin-ity.html