My personal objection is that - as far as I can tell, having a general scientific/engineering background but not being an expert in that particular field - GM technology seems to be pretty crude at the moment. "Hey lets fire some bits of DNA from this organism into the cells from that one and maybe they'll stick in the right places. And if not maybe they won't do anything bad, that we haven't forseen and can't clean up."
Strikes me as a bit like the heyday of atomic energy "let's all go out into the desert downwind of the test site and watch the A-bomb going off".
The quality's probably far more variable than mass-produced standardised factory-farmed produce and I daresay some unscrupulous retailers use the 'natural variation' clause to pass of some sub-standard stuff. However in a broader view I know that organically-produced stuff isn't fostering the worst excesses of industrial chemist^H^H^H^H^Hagriculture and, if I buy it through a local box scheme hasn't been trucked halfway across the country.