I have a one piece 2 layer Leaf suit that I bought back around 2000. Only racing a few times a year really helps keep it in good shape.
It was so long ago that I really can't comment on how they are to work with today (good or bad). I did not get the stretch panels in the shoulders and really regret it. It really limits my arm movement especially if I am reaching for something. Next suit I buy will have the arms and lower back stretch panels.
If anyone is using a 1 layer, at least buy some Nomex underwear until you can upgrade to a two layer. I used to race with a single layer proban suit, tennis shoes, single layer gloves, an M rated helmet, and no Nomex underwear, but would never do that now.
John