iPhone 5S - sticky home button

I just picked up my iPhone 5 S this morning. Immediately after opening the box, the first few times I pressed the home button, it kept sticking. So much at first that it caused multitasking to be useless. It was like having the old iPhone 4 faulty home button :)

Upon further use for the rest of the day it would only happen mostly on the first time pressing the home button after a few minutes.

Anyone else have this issue?

I'm ok with it for now, just hate little things like this. I'm worried it may only get worse as time goes by. I scheduled a Genius Bar appt for Sunday. Being that there was such a limited supply for launch, will Apple have the usual backup of replacement phones I'm stock?