I starch, I just find the fabric easier to handle for piecing when starched. Unfortunately, in Canada you cannot find concentrated starch such as Sta-flo. There's only starch in spray cans and I don't want the chemicals.
I've made my own spray starch out of corn starch that I like, but the downside of spraying is that you don't get it evenly over all of the fabric, especially the edges. So I've taken to dip starching with cornstarch. I can adjust the starch concentration to what I want and it gives beautiful results. It's economical too!