A good write up that Ian, plenty of useful snippets so thanks for that.
I'm not up on the Beemers but after checking the 530e spec's, would a more direct comparison be the GS 450H? - especially regards performance.
I can't say that I'm impressed with having to plug in the 530e. Forcing a battery regen via the IC seems to suck too, it's seamless in the Lexus.
Can the Beemer's brake regen not keep the battery topped up? Although that's kinda unfair as the Lexus will automatically use the engine to charge the traction battery.