If you're a Hunter and you're a crack shot with Hand Cannons, I don't see why not. It isn't the easiest gun to use, as you have little room for error, but if you can hit precision shot after precision shot, fast and effectively, then Thorn, despite what you might hear here on the forums, is a great gun. I never had any problems with Thorn, and I couldn't understand why people were constantly calling for a buff, but then again; without the Hunters Chains of Woe and Gunslingers Trance making up for its downfalls, there are certainly better choices. Is it viable? Yes. Are there better Hand Cannon choices? Absolutely, at least until the buff. As far as Hand Cannons go, Fate Bringer is my favourite thus far, but it's tricky to get your hands on one.