I'd take an SGSII on JB > an iP5 any day. So if you consider that the SII is likely FREE on contract, or ~$200 on a budget carrier, and the iP5 is going to be ~$200 on a 2-3 year contract, it's going to be a no-brainer for most non-Apple users. Also, Samsung is moving in their Exynos 4412 powered Galaxies into North America too, which will decimate anything else on the market in terms of raw power, and with JB, they gain that added smoothness too. I'm gonna upgrade to that GNote2 with the 4412 as soon as I can.
Jellybean(official builds) make EVERY Android device run smoother and better. ...even the older Android handsets will perform as well, or better than the iP5.
Not saying you're wrong, but I'm going to need to see some benchmarks before I believe that. That's REAAAAALLLY optimistic.