Windsurfing & Stand-Up Paddleboarding in Michigan
I've used an O'neill Boost drysuit for several years now, with polypro pants and jacket or shirt for insulation. Here are some +'s and -'s compared to wetsuits that I've found.
Along with dakine mitts, 5mm booties, and 2mm hood you can be comfortable as soon as the ice is off the lake. And you don't have to charge it with warm water or endure that initial trickle of cold water when you first get in.
You can vary the warmth of the suit by putting on thicker or thinner polypro insulation layers.
The Boost is made with a (slightly) breathable fabric so it's really nice for stand up paddling, giving you protection from the cold if you fall in but not so prone to overheating as when you're paddling in a wetsuit.
The best thing about drysuits is the non-restricting range of motion you have compared to wetsuits (even the new super stretch neoprene). It's like wearing a goretex rain jacket with no binding around the shoulders and no forearm squeeze.
It's great not having to peel off a wet clingy neoprene suit in the cold wind when you get out. You can just take the suit off and leave the insulation layers on for the drive home.
It dries out faster than a wetsuit and doesn't get funky smelling.
It's hard to find other people to sail with when it's 40 degrees.
It can be a pain to zip the back zipper by yourself.
A ripped wrist, neck, or leg seal could lead to a bad situation if the suit floods with water (hypothetically, I've never heard of this actually happening). There's a lot of buoyancy in the suit that makes ducking under waves awkward. For these reasons I only use the drysuit on flat water inland lakes not Great Lakes.
It takes careful patient trimming of the wrist and leg seals to get them right. Trim just a little bit off at a time and try on before taking more off. If you cut one too loose you have to replace the seal, so err on the side of leaving them a little too tight. You can always trim more off later.
Use chalk powder (not baby powder, which has extra ingredients that are supposedly not good for the seals) on the seals to protect during storage and make them easy to slide on.
Temporarily attach a length of cord to the zipper to make it easier to zip closed and open by yourself.
Over the past 8 years a few tiny leaks have appeared in my suit, probably from rubbing the edges of the harness. Silicone sealer works pretty well as a fix. You can lay a patch of fabric over the wet silicone and let it dry for extra durability. The trick is finding where the leak is coming from. One method is putting water bottles in the seals, filling the suit with air, and running soapy water over the suit to find the leak.