The magnitude of the changes that are possible now are so far beyond what was available with selective breeding, it's nonsensical to consider them in the same league. I wish people would stop trotting out that argument.
The pace, more than magnitude, of changes achievable is greater now (either with GMOs or mutation breeding) than with older forms of selective breeding (mutation breeding is, after all, a form of selective breeding.)
Seems a step or two removed from selective breeding to me, though I'm not arguing for or against GMOs, just saying that it seems to me there is a definite distinction between the processes and what they are capable of doing.