Depends what you want it for.. if you want it to flash and show off, then go for it. Really, how many people are actually going to grab your wallet and examine it?
I personally go for the authentics because to me, it's more about the pride of getting something nice out of some hard work. Like GQ says, a man's wallet and watch define who they are.
But to answer your question.. of course you will notice some differences if you have both side by side.. more or less depending on the quality of your fake. But most people would hardly be able to tell a replica from an authentic that's been used for a few months.