In our case the radish and cereal rye is going to be grazed by our cattle, so there is one benifit. This is first year out of the last few that we have planted radishes so not much experince with them, but i know one thing the cows sure like them.  You are not going to get a response every year (in my opinion) to cover crops, but in years like this one wet early, then dry later on, the cumulative affects might be showing up. Think about it, if you had some type of cover on the soil,you could have saved 3 inches of water that would otherwise be lost to evaporation. I could go on and on, but i won't.