I was walking through strictly sail this weekend in Chicago, and I found a couple that seemed interesting. Mercury seemed like a nice boat for the money. But then I also got to talking to the owner of big dog boats:
Big Dog Boats
They seem to also make a nice boat with thicker material than the other guys. And, I think they are just two enthusiasts that decided to spec out these boats, and have them built in China. One of the guys is an airline pilot, so he gets over there regularly to inspect the build process. In that they are trying to break into the market, they seem to offer a very loaded boat with tons of features. And, usually at the shows, you don't get to talk to the owner that is extremely knowledgeable with their entire process. I guess the risk is that they won't be around to give you the warranty service.
We bought a hard bottom west marine hypalon at the Miami Boat show probably 4 years ago. It has leaked twice, and been a big hassle to get warranty service.
The next dinghy I buy will be a pvc roll up. The air bottom and keel is a compromise, but you can add these rub strips on the bottom if you think you are going to be hard on it. They usually have one right down the center.
I would go with PVC because they will last a long time also, and if you roll it up, it wont be in the sun. We cover the hypalon one anyway because it would get all chalky in the Florida sun. And, PVC is significantly cheaper such that you can just get a new boat when it falls apart.
We use a 15hp 2 stroke on the west marine hypalon, and planes at 18mph which adds a ton of flexibility in where we can anchor and how far we go in the dinghy. So, if you could get a setup that planes, you might be very happy.
And, I suspect that your 5 hp 4 stroke weighs almost as much as our 15 hp yamaha 2 stroke. However, 4 strokes get better gas mileage which you probably want on your sailboat in the first place. Just something to think about.
When you do your Lake Michigan trip, don't miss Charlevoix and South Manitou Island. But be ready for the black biting flies. At Annapolis one year I saw these outfits made out of mesh that allowed the wind to blow through but protected from bugs. These never seemed to catch on, but you will be wishing you had something like that.