The Kanatis are great bows, but you are limited to one model and a set of choices for customization. Nothing wrong with that at all, Jason has found a formula that works quite well. With Gregg and his engineering background you have a bowyer that's continuously trying to outdo himself.
What I can comment on directly is the Elkheart vs the Helms Deep. I have owned both and currently have a Helms and one of Greggs last Shrews, a special one. I own The Helms as a representation of Greggs current work and the late produced Shrew as an example of Ron LaClair's legacy to trad archery and Gregg's artistry. The Helms and Elkheart are very very close in character IMHO. Gregg can provide/confirm on the draw force curves but to me the Helms is just a whisker smoother while the Elkheart is just a bit quieter. I would say it comes down to do you want a recurve with its curvy shape or a longbow. I like both so I own both. I sometimes liken the Helms to an Elkheart that had the limbs pounded flat and recurved on an anvil. The character differences are subtle and certainly apparent if you can shoot them back to back, and Gregg can certainly weave in some tweaks on a custom to suit the individuals preference. I would take either into the woods and know I had one of the most purist hunting bows currently available. In a traditional wood/glass bow it is hard to beat the pointability or manners of these bows. I have always felt that they shoot like a bow 6" longer.