I bought a boatload from Tayda expecting to pitch the bad ones, but they have all been fine so far. I also bought a few from small bear and have auditioned both varieties in delay circuits. I didn't notice much of a difference between the SB and the Tayda variety. The 2399s start to give you trouble at long delay times, there is a trash can sort of distortion on the repeats. When I build a delay pedal, I usually test a few chips out to minimize this.