I live about 15 miles from Duane's shop and have owned several of his Heartstoppers. All 1 piece or 2-piece though. I have shot the 3-piece on a few occasions when I've stopped in. I have never owned or seen a Thunderhorn that wasn't a work of art. Duane has an incredible eye for detail and all of his bows shoot very well. He had his own 3-piece for a long time testing and tweeking it before putting them on the market for the rest of us.
If I was in the market for a quality, well-built, easy to shoot 3-piece longbow, I would not hesitate. I think you would love it.
You don't see very many for sale used, so those that buy them must hang on to them.
P.S. I am in no way paid or endorsed by Duane, just like his bows (though I don't own one at this time).