Is it not the case that any RAM will work in a Mac? I was of the belief that any SO-DIMMs purchased from retailers like Newegg will work just as well in my MacBook as they will in a Windows-or-Linux-based computer.
That may be the case I think with the Intel machines - as long as you're buying the proper spec'd RAM. Based on reports I've seen with the PPC Macs, that was not the case.
However, I have seen quite a few newbs here purchasing the absolutely cheapest RAM they could find at newegg and then it didn't work.
For those that know hardware and know the brands to buy and those to stay away from, newegg is a great store.
For the non-hardware enthusiast, OWC makes it simple by asking which Mac you have and then showing what they have that will work in your machine. And while their cheapest stuff may not be as cheap as newegg, it's typically pretty darn close to it.
I've been building my own rigs for 15 years now, and I don't buy anything from newegg for my Mac without also checking at OWC.