I own several J-45's and have played all the latest derivations (J-15, j-35) and have not found the quality control to be any different from other manufacturers, both in tone and construction. Quite the contrary, these under $1600 Gibson's have been all above average to great. I'd avoid the rosewood j-45's as I've yet to hear one I like, though. Just personal preference and adaptation to what I've always known I suspect.
I also suspect that a lot of Gibson animosity comes from Gibson management's less than favorable standing amongst the tree hugger, labor union and granola eating crowd.
Bottom line is to play as many as you can, particularly someone's acoustic that has not been hanging in a big box store with dirty strings.