To me, there's no difference in taste. If someone didn't know they were eating a bison burger, they probably could not tell the difference. There's substantially less fat than beef. So it's much healthier, but can get dry quicker. That's easy to fix, though. Just be aware of...
Buffalo is delicious and much healthier than beef according to the USDA.
60% to 80% less fat (depending upon the cut of the meat.)
35% less cholesterol than beef (+less than chicken with the skin removed.)
30% higher in protein and less calories.