Well, I have only tried the jacket-style BC once, and I absolutely hated it. I have tried the back-inflate BC more than once, and I have hated it.
Just Kidding! I warn you that you are getting the advice of a new diver, and my advice will never be best.
I really do not prefer the jacket-style BC. I found that it was very uncomfortable on the surface, and that there was a lot of restricted movement underwater due to the jacket. I love my backplate wing rig, and it feels like heaven! One arguement I have heard from a lot of dive shops is that with back-inflate, if a diver ever becomes uncontious underwater, he will not be upright on the surface, and will have his face in the water. I really am not concerned with that, as you should be diving with a body at all times. Also, just recently jacket-style BCs have started to come with a removable bladder, so if you tear the bladder, you do not have to replace the whole BC, but only the damaged part. The back-inflate backplate wing system has always been like that, and is much more adjustable than the jacket-style BC. Also, when upgrading to doubles on a jacket-style BC, you must get a whole new BC that is larger. With the back-inflate backplate wing system, you can keep the plate, and only change the wing out, often saving you at least $100. Tests have also discovered that back-inflate backplate wing systems have much less drag than the jacket-inflate systems, giving those who use DPVs such as scooters a longer usage period. Also with a jacket-style BC, you can only put a certain amount of weight on the BC, as there are next to no places to put it short of having a weight belt. With a back-inflate backplate wing system, weight belts are only an option, as there are tons of places to put weight, enabling better trim in the water. (you can put weight on the tank bands of a back-inflate system, automatically adjusting your angle in the water. Something that is almost impossible with a Jacket-style BC.)
I prefer back-inflate, and will always prefer back-inflate!
Just my 2 euros...
Taylor