I've never really had any issues with RAM reliability, but I do tend to steer towards name brand memory such as: Kingston, Crucial, etc..
I usually look at the warranty info as well.. Why would I buy memory that has a 90 day or 1 year warranty when another manufacturer offers lifetime ? If you are not willing to stand behind your product with a decent warranty then why should I risk buying it ?
Warranty: Kingston offers lifetime warranty† on all memory modules, boards, and flash cards.
Terms of Limited Lifetime Warranty: Crucial warrants to the original end customer of its products specified below that its products are free from defects in material and workmanship....
There are other good manufacturers out there I only listed these two as examples.