I have one bike with Apex and another with Rival. I feel my Rival bike shifts/operates a little smoother than the Apex bike but both are very good. My Apex bike has Tektro brakes, the Rival brakes are significantly better, however, the Apex brakes may be better than the Tektro's also but I don't know for sure. I should put them on so they match though. both bikes have shimano 5700 cassette, 12-28. both have SRAM 1071 chains. it's probably as simple as the rival bike being dialed in a bit closer to perfect than the apex bike. good stuff, I don't think you'll regret it.