SAT Works awesome in BE, I have the KS mod with (BE,C45,HBE) with the FAT,SAT,SFX loop. I can mix the SAT in either mode, same with th FAT switch to beef up Single coil pups.
The SAT switch is the best part of my amp. I don't know how I could go without it. I use the C45 and FAT switches occasionally, but the SAT switch is always on.
It should be called the "Key to 80's Metal Switch" because that is exactly what it does. I just love it!