I actually own the 1st flight suit and use it for cold days on the motorcycle. In the end, it was too baggy even though it is rather close fitting. Plus, way too many zippers and do-dads to take off. I like the Proban racing suit and ordered one for the long haul. It has the best specs and wear, plus the mandarin collar.
In the interim, I found this suit and it fits really nice. If you get one, go with your business suit size.
http://www.automotiveworkwear.com/RedKap/CT10/coveralls.html