I was browsing the soybean net income statistics reported by the University of Minnesota for the 2011 crop year. There were 1,372 farms reporting soybean statistics for 2011 and 680 used some type of chisel or reduced tillage (635 gave no answer on tillage practice). These farmers reported an average of $147 return over direct expenses per acre. However, the 11 farmers reporting using ridge till increased their gross return by about $60 per acre and their net return by $30 (even with cash rents averaging almost $40 higher).
Although the sample size is too small to be totally meaningful and with higher cash rents suggesting better ground, it is still productive to review these reports each year and determine the trend. If you get a rolling five years of history and one method of farming consistently out-yields the standards in your area (or your farm), it may be wise to consider trying the method on a couple of test plots. These tests may give you the knowledge to make an educated change and join the farmers in the top tier.