So many variables here that it is hard to say. As far as what I have personally felt there is very little difference. The science is compare the energy of the rounds. In the same weight rifle the one with the most energy will recoil most. Then there are unquantifiable factors like stock shape. The reason that these two rounds are so popular is that they are very good compromises between the energy they put out, rifle size, and most peoples recoil tolerance. I would say that if you don't like the recoil of your 270 you are going to have to take a considerably bigger step down than 308. Maybe something like one of the 6mms. Are you sure that it is the recoil that you don't like or the noise?
You are wise to admit that you don't like the recoil. I have seen so many guys who won't admit that they have too much gun, and are poor marksmen as a result.