I think it's very unfair for you to come here, and blame this on the other people responding to this thread. All of the good places to buy RAM (Crucial, Other World Computing, etc.) all have search features that allow you to specify exactly which Mac you have so that you can be matched with the correct memory. I ordered a 16GB RAM upgrade for my Mac Book Pro Late 2011 from Crucial. I got the right RAM, and it has worked flawlessly since I installed it in September 2012. I'm also running my Mac mini Late 2012 with 16GB of RAM also purchased from Crucial. Officially, Apple does not "support" 16GB of RAM in my MacBook Pro, so if I ever have to have warranty work done, I'll just put back the 8GB kit that was originally in the system. No worries there.
In the end, it's YOUR responsibility what you put into your Mac. If you don't do the right search to find the correct memory, and you buy cheap components, the trouble you have as a result is YOUR fault. These support discussions are for us to help each other, but why should we even try to do that if someone is going to blame us for their problems? I'm an Apple Consultant, and I give my customers advice every day about what they need to buy to meet their needs. If they cheap out at the last minute, and buy crappy products, that's their fault, and often, I will refuse to support those crappy products. Blaming me for not following my advice will leave them without an IT consultant.
The lesson to be learned here is to always do your research, and make sure that you buy the correct components from good vendors. Don't let the prices sway you more than getting the correct products. I had no idea how many volts my RAM needed to run on, but I didn't need to know anyway since I bought my RAM from a vendor who I trusted to match my laptop with the right RAM.