Tim is correct, GFCI should not be more sensitive, but my experience has been somewhat different from my expectation. I do know a "regular" homlife style breaker, can actually take 2X it's rated capacity for an unexpectedly long time. I think GFCI breakers just have a more instantaneous trip curve. I had the GE and SQD trip charts somewhere for the standard breakers. Might be interesting to compare.