Although we both like buffalo meat, we find the hamburgers way too dry for a good tasting hamburger. The only time we got bad buffalo, was a roast we bought at a small meat market in So. Dak. somewhere. Since it was near the end of summer, or at least not "in season" for fresh buffalo, we think it had been either frozen too long or frozen, thawed, frozen, thawed perhaps too many times. It was really tough and I had done it slowly in the crock-pot.
As for weird places to buy buffalo meat, we found a ranch in central/western Maine of all places, a few years back. We bought quite a bit. The owner also owned a large ranch in So. Dak. somewhere and did this as an off-shoot. We stocked up and enjoyed it all. A year or so later, we heard the owner got gored by one of his critters, and was severely injured. Never learned how he came out of that.
Daisy