..before folks start talking about how ounces add up, I get that. But with a decent IWB holster weight really isn't a massive issue..
No, not a massive difference, but I definitely notice the difference between my PM9 and LCP. I'm simply more comfortable carrying the LCP in my own environment - suburbia, Home-Depot, Wal-mart, etc.
The difference is even more noticable in the summer with just shorts and a t-shirt.
The PM is just a bit fatter, a bit heavier, and prints a bit more... all enough to make the LCP more desirable on a hot day.