I always max out my systems with the most RAM possible. Boosts things up and it's cheap nowadays for the new stuff. It's worth it, trust me. I work on these things for a living, and RAM is a great upgrade for the money.
I put 8GB in my 17 inch 2011 MBP from 4GB, using these:
http://www.newegg.com/Product/Product.aspx?Item=N82E16820231266
$79.98 shipped, and it's 1333 speed, fastest you can get for the new MBP's. You don't need "Apple Memory", just do your homework, read the reviews, and at the end of the day, RAM is RAM. It'll work unless it's defective.