I notice my M&P9 is more sensitive to where I place my finger on the trigger. It groups just fine either way but the midpoints of the groups will be an inch or two apart.
The biggest danger I've found with the 9c is if you hurry a reload and don't get your finger out of the way you can end up with a blood blister from getting pinched between the magazine base and the grip. I've a class coming up next month and anticipate getting pinched a few times. I mostly shoot a full-sized M&P45 and didn't anticipate this particular problem.
"What kind of man would put a known criminal in charge of a major branch of government? Apart from, say, the average voter." - Terry Pratchett