I have the LC9. Bought it in August after I asked Springfield Armory if they were coming out w/ a CC piece. Customer service rep said they'd been told nothing--and I believe she was telling the truth--so I bought the LC9.
I felt the LCP was simply too small for me, too small to handle well--plus I don't like the .380 caliber. A 9mm was the minimum for me.
The advantage of the LC9 is that it's thin, .9" in width. I have a CC holster for both the XD and the LC9, and the XD is just very lumpy on my hip.
Another advantage--though it's something to which you have to adjust--is the double-action trigger. It's a good trigger, but of course you have to cock and then release the hammer with the trigger pull.
Why an advantage? I don't want a hair-trigger CC weapon.
The downside is that if you're used to the XD trigger, it'll be different. I switch back and forth between my XDs and my LC9 at the range, so I have learned how to use them both well, but there's a significant difference.
Interestingly, in learning the LC9 trigger, I've found it's made my trigger pull on the XDs better.
Here's a pic comparing it to my XD-9 Service. I've since cut a small piece of inner tube for the grip of the LC9--that's what you see on the grip of the XD-9. It adds just enough tactile feel and girth that it makes it fit my hand much better: