Parenting the cloth can be really useful if you want the cloth to be tighter or looser in the final frame. If you have a tight clothing, and your figure is a bit thinner, with a parented cloth you can scale the figure in the starting pose, and it will get a chance to stretch a little, even with a thinner figure. Works like a charm for me. The opposite can work too.

With some clothing, I actually get prettier drapes with quads than with triangles, despite what other testing results say. It depends on the item, so I just go with what I think looks best for each thing. :)

Also, how the polys are modeled are also important. It's important to shape polys so the fit the angle of collars, seams and things like that, which will result in much nicer drapes. Also certain areas should have enough polys, like knees, breasts etc. I find that those things are often more important than whether quads or triangles are used.