I atribute leaking air to aluminum rims more so then tires theirselves.
I had a set of michelins came on a 1996 dodge truck (steel rims) and never wore them out and they held air fine. I pulled them off the truck because of no traction but they still had about the minimum tread depth left and worn evenly. Ever other brand I put on after those worn funny and quick. I never have stepped up money wise and bought more michelins.