My Sonic behaved fairly well when purchased, but much better after replacing the stock wheels and tires, so I have always attributed people's complaints about dodgy steering to the Hankooks.
However, this thread makes me think that there's something weird about a sensor, and that maybe it's not my tires, but rather that when they replaced the tires they also managed to accidentally bump the sensor in a way that made it work right.
If this is the case I owe a serious apology to Hankook... and have a bone to pick with GM!
That said, I normally drive around with both on, unless I see a spot where I'm going to do a hard start. Even then, I kill TC and leave SC on, I rarely get "wavy gravy" from SC, and even when I do, it doesn't seem to make any difference to how the car drives. I'd still turn it off, but I'm lazy, push and hold for several seconds is annoying, while just a tap, that's under my threshold.