My other hesitancy is the transition curve from jacket to back inflate. I only dive for a few days once or twice a year, so I don't want to spend my whole trip trying to figure out the new system. But the people I spoke with today gave me more confidence that switching isn't that difficult, and it is mostly a difference at the surface.
IME the main difference is you pump up the jacket and it holds you up straight, way up. With a back-inflate you need to give it a small puff and float with just your head above the surface. Which may be less comfortable, especially in a chop. OTOH if you need to swim, about the only way you can do it in a jacket is on your back, turning around all the time to see where you're going. With the aircell on your back you can comfortably swim on your front.