I read somewhere that the breathable rating is just a number that should only be used to rate products within the same company. And I can confirm that the statement is true.
My DC Angstrom (10k breathable rating with eVent fabric) jacket breaths ALOT better than my Special blend autograph jacket (15k breathable rating with Gore-Tex). The difference was like night and day to me. I can wear my DC jacket with the same amount of layers and stay just as warm, but never too hot and stuffy. With the Special blend Gore-Tex, I would start to feel stuffy after a couple minutes.