Shorty suits are very comfortable and easy to take on and off.
If/when I wear a shorty, I pretty much always have a full lycra (dive skin) underneath, which I leave on during the full day on the boat for the critical sun protection. A lycra suit (especially with a nylon hood) is effective from most stingers and pretty much 100% from the sun. A full 3 mm suit is too hot to leave on during the surface interval, for a good bit of the season. So you are gonna need a lycra top, no matter what suit you wear - is my thinking, anyway.
You can also buy separate lycra pants and top, which is more convenient than a typical lycra scuba suit, if/when you need to relieve yourself.
