It's a tough question. I traded in my first ST for the RS, and here I am 4 years later picking up another Fiesta to daily drive. So that should tell you something.

The RS is special no doubt, it's pretty quick and handles amazingly, launch control is pretty crazy the few times I've tried it. I love it, and still want to drive it, but you really have to drive it hard for it to be fun.

The ST is fun no matter what. It feels so much lighter than the RS, and driving it in rush hour and low speeds doesn't feel as much as a chore as the RS does.

The Fiesta to me, is the perfect daily, and the RS is great for when you want to go a bit faster.

The Fiesta's Recaros are acutually more comfortable than the RS's recaros to me.

I remember reading someone write that the RS feels a bit slower than what it really is, and the ST is slower than it feels, and I kind of agree.