After flying the B2, the 1.5 will feel almost like a zen feels to the rest of us. The B2 is much easier to axel, which is fun.
I couldn't agree more about the B2. When I've been flying my B2 full vent and I switch back to my 1.5 it feels for a while like it's in slow motion, a LOT like going from a 1.5 to a Zen. I pulled off my first axels recently with the B2, something I'm still working on with the 1.5. And this kite practically flic-flacs itself at any angle, another thing I'm still working on with the 1.5. Doesn't feel as precise to me as my 1.5s and in my hands it's less graceful, but loads of fun.