I am loving knitting the sweater vest... :)
But as this is a first for Fair Isle I have discovered that you really have to pay attention to what you are doing. I have had to frog several rows once I get to the end and realise that the pattern is out by one stitch. And it is so noticeable, not the kind of mistake you can get away with.
I have just started decreasing for the arm-holes, which means I have to pay even more attention. Decreasing and different coloured stitches eek!