Sleeveless is definitely a little easier in transition. They are also cheaper and plenty warm enough for that swim. You used to hear people say that it was also better for flexibility but I don't think that really applies anymore with the advances in neoprene technology. With all that said, if you're thinking of doing anything in colder water some time... like Alcatraz.... get a full sleeve. There's no point in having 2 because the advantages of the sleeveless over the sleeved for warmer water do not out weigh the cost of buying 2 wetsuits.