I would say that, as a whole, the answer is that both countries would do about the same, assuming their only difference was the black and white political difference of "left vs right". This kind of political ideology may create a great deal of controversy and discussion, but in most areas where you might measure national progress, it couldn't possibly matter less.
Political ideas are of course at the foundation of how a society prospers (or not), but the idea that the left vs right divide is the important one totally misses the point. National political views go beyond the two simplistic choices, and I'd argue that common positive factors around the world hold true whether the people in question are lefties or righties.
Look at the number of successful countries around the world that lean one way or the other...