DK , I have had both.... I carry a Nimrod as part of a TXTF2 USAR. The Nimrod is a excellently made pack, it is versatile and can be made into many different combinations. You could get to camp , then break it down and have a daypack to hunt with. They Carry well and can be fitted to your frame. Overall, a good solid , flexible pack.
Bisongear.... I own two... A Outfiiter with Shoulder Straps, and a Lost River. All I can say about Bisongear, is QUALITY, CRAFTMANSHIP. You can Customize them while being constructed and accessorize them with extras afterwards. Angelo sent me a Insulated Canteen Holder for my Outfitter, I liked it, but I could not fit a Military Canteen Cup and the Canteen into the holder together. I called Angelo, he had me ship it back along with the Said Canteen/ Canteen Cup combo, and they remade the holder to fit at no charge.... That's Customer Service. Bisongear , being made from wool is so quite to carry vs. the Nimrod Material.
I do not think you'd be unhappy with either, but I Think You'd be Happier with Bisongear. However, this is just one mans opinion , but I think I have plenty of backup here on that.
Tu Compadres, Sutty