The question isn't one of performance as much as it is warranty.
Kingston, Crucial, Corsair, OCZ, Geil, and other name brands almost always carry a lifetime warranty on all their memory.
Often you will see generic crap for sale that offers a "lifetime warranty", however getting them to replace your RAM is often an excercise in futility. The big boys all have good support systems and don't usually fight with you over RMA's. (I can personally vouch for Corsair and Crucial, they are great about replacing bad RAM).
Also, generic RAM is (generally speaking) less reliable and less compatible than name brands.
I have Kingston Value RAM (ECC) and it's treated me OK. Every now and then I have to switch banks in my motherboard because it refuses to POST lol.
Who knows. I'll use it till it dies. It's on my P4 478 anyway.
I'd say spend the extra $20 or so and get the good stuff, preferrebly something with a better CL. You probably won't notice a difference, but it's worth the cost, and a lot of little improvements here and there do add up when builing a system.