I'm currently making this sweater in the purple/mauve/burgundy/grey colourway, and find that the stripes are coming out of an even width. Your sweater has much more "random" stripes (very nice!) and I'm wondering if you changed yarn colour occasionally yourself, not waiting for the yarn to change by itself? Incidentally, I'm making the sweater much longer - hip length, in fact, - about 6" longer than the pattern says. I hope it turns out okay!
Created by: Patricia S