I just checked out their website. Many of their gruits sound interesting. I doubt I'll be making a trip to NH any time soon, so I doubt I'll get to try any though. :-\
Making these things seems much more difficult that brewing regular hopped beer. With hops, it's all been pretty well figured out and standardized, at least when it comes to what types of hops to choose, how much to add, and when. This might also be the case with some more classic herbs and spices, but using "random" herbs would need some experimentation, which I imagine would be pretty time consuming.
There are a lot of Ethiopians in this area and I work with a guy who was telling me about Tej (mead) and Tella (bread beer), which both use gesho leaves as a bittering agent. I think this may be my first foray into this type of thing, because this guy can tell me if I got it right or not. I really want to try a tella recipe using teff, sorghum, and gesho leaves.