Definitely not a slow boat by any means. It's got the same performance, but it will feel a bit heavier. The Sunsports I've driven were all very quick, and handled great. Now my big ole Saltare definitely is a big boat, but the 454 still makes it jump up fast.
The Comp is like a ferrari, the Sunsport will be like a pickup truck. The Comp will be fast and handle well, but you can only do so much with it. The Sunsport will handle well, can go fast, but can haul and can tow, and is much roomier.
187 hours on a 1990 Mariah???? That boat should be in pristine shape, or is a wreck. Post some pics of the boats you're looking at. I understand if you don't want to show the direct links, that's fine. But show us the pics of the boats. It's amazing what we can tell just from looking at them.
There is no question that the Sunsport would by my first choice. While I loved my old Comp, I would not recommend that to someone if a bigger brother is available.