I just went from a 16 lb small jacket to an NRS Rapid Rescuer. I like it, I am in the middle of its adjustability and I can get it good and snug in every aspect. I am going to have to swim in it more to get used to having all of the extra flotation. I can have a hard time going from by back to my stomach or vis versa when swimming with hi float jackets. I tried on an Astral Green and it was too short for my long torso.
I agree with trying some on first, but it is pretty difficult to find a store with a selection. I took a risk and ordered mine from the interweb, but I figured NRS would take care of me if it turned into a total failure. I got lucky this time.
Wishing I was on the river instead of surfing the web...