Between my mothers house and mine there is a large pile of quilts made all different ways. I don't see any problem with polyester thread since some of the older quilts were used hard, washed often and there is no problem with the threads or fabric cutting.
My mother just requested that i make her 2 quilts for one of the kids rooms, she has 7 kids under her roof (not including the adult child living in the basement "man cave") When i asked her how she wanted them backed and quilted she specifically said to just use regular thread in a neutral color. To us, regular thread is the polyester general purpose stuff.
These aren't meant to be heirloom quilts, if that was the case i would probably go with something nicer just because of a larger selection of colors. I would probably also want to hand quilt but my skills aren't that good yet.
I am going to guess about this but if there was a problem with various threads, then how can a quilt be made with the clear mono-filament type stuff ??? It's like very fine fishing line that you would think could eventually saw through the whole quilt.