Hmmm.... a bit of deja vu here. I'm thinking you called me with this same question a bit ago. And if not, somebody out there is reading your mind! :o)
The Henderson line of wetsuits are a very high quality line that I'm sure you'd be more than happy with. The H2 is extremely stretchy and comfortable, but sometimes for some folks its a bit too elastic. While suitable for anybody looking for extreme comfort and mobility in their suit, it's most useful for those who do not get a nice or proper fit in an off the rack suit. having 200% the elasticity of a normal neoprene suit, it expands and stretches in spots that the diver isn't dead on in terms of sizig, offering a custom like fit! That fit equates directly into warmth as less water is pooling inside the suit where it shouldn't be.
The Thermoprene suit isn't quite as elastic as the H2. The main thing that will give you is a slightly better price. If the suit fits you well, you'll still enjoy it's warmth and the extra mobility you'll gain as this material is 75% more flexible than the standard neoprene suit.
Either way you can't go wrong with your choice. The quality of either suit is top knotch!
Lastly, it's not uncommon at all for people to use a 5mm suit in Hawaii, although except for the middle of winter it's often a bit warm for Caribbean diving/snorkeling. The nice thing about that is that you can always make a warm suit cooler by simply unzipping it a bit, where as you can't make a cold suit warmer unless you add more neoprene layers to it.