wetsuit deliberations

I am gearing up for the Great Chesapeake Bay Swim on Sunday and can't decide whether to wear a wetsuit. I went for a practice swim at Sandy Point last weekend and practically melted in my wetsuit. I ditched it after about 500 meters and felt so much better. I also felt like my stroke was more natural and efficient. When I checked my watch, I was actually swimming faster without the suit. And looking at my race results over the past few years, I haven't gone noticeably faster when I've worn the suit (but how do you compare between different races). I've done a little research, and the water temp close to shore last weekend was 78. In the middle of the bay it was 75. Today, the middle of the bay is 72.7 (at noon). It could go up a little more between now and Sunday morning, but who knows. Somehow, almost everyone in this race wears a wetsuit. People have told me that the buoyancy is really important in the shipping channels, where the water can get rough. And everyone tells me I will be faster with it. That advice makes me feel like swimming without the suit is irresponsible. I could really use some perspective, especially from veteran GCBS swimmers. At those water temperatures, is there a reason to wear the suit? Are there other people who feel like they swim more naturally and maybe even faster without it? Thanks!