I use them in my rig. OC'ed up to 3.8ghz without having to change any settings on them. That's about as high as I dare on stock cooling though.
The timings aren't great, but they aren't bad either. When you consider the speed these sticks run at, it makes sense. Crucial Ballistix have 4-4-4-12 timings, but they also run at DDR2 800 speeds.