When you do intarsia or fair isle, with lots of ends and sometimes varying weights, the knitting may be great,
Pick up sts for you edge one full st away from the edge to give wide berth to the wobble ones that both look bad and will be loose and create an unstable edge.
When you work around a corner (armpit, neck hole) mitre for ease - I do this on single thickness rubbings, or if you're doing a folded edge, decrease a couple sts on the outside, then increase them again to match in the inside. This will make the peice lay flat, especially if you're going to wear it layered like this vest.
When you do a folded over edge, make the inside a couple rows longer than the facing side. Again, it will ensure the edging lays flat and gives you a nice, stable and solid backdrop for where you picked up for your edging. That way if you're layering, nothing will show through your pick up.
I'm also thinking about doing some of these and putting them on EBay. Or setting up a link to submit a picture showing colors you like and I'll make you a Fassett sweater or vest. I could do 5 or so a year. Any thoughts, takers?