I've had my share of bison burgers plus bison steaks ... not to mention antelope, deer, moose, ostrich, etc. I can't tell you all of the figures but bison meat has a higher percentage of protein then beef and less cholestorol. After some quick searches on the internet and from just skimming, it says about 30% more protein and 25% less cholestorol. Here is a website that compares bison, beef, pork and chicken and I think will answer most of your questions.
http://www.tonysmarket.com/foodhealth/bison_info.cfm