I know people who have tried and been successful at times. There is a lot of big money in that spread right now and certain days it dominates the movement in those fixed income products. Usually one of them is locked in a tight range while the other product is moving around a lot. I think certain days you can do well trading the trend of the spread especially if you have fundamental reasons behind you based on an economic release or change in talks or hints of a interest rate policy change. However the spread can turn on a dime and you won't see it coming.