I guess I must be the sucker that is reborn every minute. There is really no correct answer to this question. Better to be silent and thought a fool, than to speak and remove all doubt, but here goes.
I am sure there is a scientific answer, but as a practical matter, there is no difference in distance for the average golfer. This is assuming that you have identical lofts, lies, shafts, and balls. I think the average golfer will be more consistent with the cavity back and therefore his average distance with a given club may be longer, but his best shot with either will be about the same for practical purposes, ie difference of 1-3 yds.
With either my Titleist DCI 5 iron, or my Wilson Staff 5 iron, a good, smooth solid summertime strike is about 165-172 yds with a good ball. A perfect (for me) strike with either is about 175. I almost never hit it perfect. If I hit ten new balls with each club, the best of each group will land about the same; but the group hit with the DCI will be twice as close together and the center of the group will be 2-4 yds longer. My Titleist says 28* on the 5 iron. I don't remember the loft of my Staff 5 iron, but I did have it bent to play longer than my 6 which was bent to play longer than my 7 which was bent to play 150 yds for a stock shot.