Have been to both. Neither what I would call a 'natural' setting.
Prefer Griz/Wolf Discovery Center. Bears still a little fat and hand fed They did interact with each other and were pretty normal looking. The wolves there are awesome.
The BEARS at Rexburg are Extreemly fat and Waddlesome. You DO get to drive into the compound on a prescribed route ~ thru a few trees and bear 'houses'. Bears meander all over.