I have a Nessmuk double bit made by Lee Reeves. The different edge angles give me a fine edge and a steeper edge.
In reality for my usual work, where I use a short hand ax, I think I prefer a single bit with a poll. I have not found the choice of edge angle to really matter for me, but Nessmuk spent a lot of time building shelters, browse beds, and a host of other things that just are not part of my woods experiences.
My GB Hunter's Ax is my favorite in this range. The smooth poll is great for pounding cedar bark for tinder nests and the size and shape of this ax coupled with the fine edge is perfect for my uses.
I love having the Reeves Nessmuk ax but do not find the choice of bits all that important to me.
I am going to probably order a Reeves Single Bit next year. His ax work is perfect.