I use a bitmap app to rough out my Illustrations. TVPaint or Sketchbook pro (currently) Roughing out should be about freedom, well, in my case it should be. I then clean up in Xara. I agree that Xaras unsmoothed (Or lines with little smoothing) lines are pretty awful from a hand drawn point of view and are not much use for sketching. For clean up it is a different matter.
That said the new shape builder tools are pretty exciting and I have high hope for the future. Drawing gesturally (freehand) is a much quicker way of doing things than point by point. Fingers crossed that Xara can develop in this direction. (the faster we can do things the more we get paid. Right? :-))

Huge Regards
Dave