There is no preferred chain ring where I ride. The terrain around here has many long grades in the 5% to 15% range and a few up to about 25%. For every 10 miles there's 1,000 to 1,500 feet of climbing. It would be silly to stick with one chainring. I use every single gear ratio on all my bikes. I shift gears based on keeping a reasonable cadence (though sometimes this isn't possible on the steepest grades).