I've got a Sharkskin Chillproof rear zip and love it. It was $350ish.
It's plenty warm, extremely flexible, and neutrally buoyant so you can dive less weight and don't have to worry about neoprene compression w depth change. They're also machine washable.
Chillproof Suit (Male)
You are diving in the tropics and surface in your 3mm wetsuit to find a substantial breeze has picked up. You find you are getting cold, even while your wetsuit is on, because your body is wet and the wind is cutting through the suit. That is one of the reasons why divers prefer the Sharkskin...sharkskinusa.com
I'm not knocking the Chillproof ... but I AM going to knock their advertising.
Their site says:
You are diving in the tropics and surface in your 3mm wetsuit to find a substantial breeze has picked up. You find you are getting cold, even while your wetsuit is on, because your body is wet and the wind is cutting through the suit.
That is one of the reasons why divers prefer the Sharkskin Chillproof suit. This suit has the thermal equivalency of 3mm of neoprene.
I'm calling BS on that.
First, no, wind does not cut through a neoprene wetsuit. Neoprene is wind (and water) proof. It is not even breathable, which means, technically, it is MORE "windproof" than a breathable material.
The reason you get cold so quickly when you get out of the water is that the wind is drying the moisture off the exterior of your suit. That moisture is carrying away heat. It's called evaporative cooling. And, if the Chillproof suit is wet, it will have the same experience. If the exterior dries a lot more quickly, then maybe you would not get AS cold.
The way to stay warm after getting out of the water is to either peel your suit down or off and get dry, or put on something over the suit - like a Surf Fur or other boat coat - that keeps the wind off the wet exterior of your suit. (I LOVE my Surf Fur!)
And secondly, I have not dived a Chillproof. I have dived Lavacore which is similar, but I can't say it's the same. Regardless, I call BS on being as warm as a 3mm wetsuit. MAYBE it is as warm as a really low quality 3mm. But, again, just my speculation here, I would bet money that anyone that tries them both would find that (just for example) a Bare Reactive 3mm is quite noticeably warmer than the Chillproof.
Again, I could be totally wrong. I have not even held a Chillproof suit in my hands. I would love to be proven wrong. A suit that is as warm as a 3mm Reactive, for almost half the money, would be awesome!