If you like the fiber optic sights, the choice is obvious. I don't. I have a 9L and have picked up a couple, in places where I could snap them. They have seemed pretty good, to me - not a lot different than the 9 Pros I have checked out. I have an early M&P40 with a bad trigger, so I know the difference.
I am waiting (patiently...) for an M&P40L.
I would buy the 9L and go have a nice dinner somewhere, saving myself the annoyance of the silly sights.