So, just drove from Bath to Bristol, then to my mom's in the West Midlands, then back to Bath. Round trip of 216.7 miles according to the car (which tallies with Google maps). Battery level was at 100% before I set out (no preconditioning or anything) and I just got back. Total time in car, four hours, 25 minutes.
Now, it's been a lovely warm day, with little or no wind, I haven't hammered the car (bar a few little testers!) and a good 95% of the journey has been on motorways, set at 72mph in Eco Pro (that's probably 70mph as BMW overestimates speeds). Air con was on, at a comfortable 19 degrees. Unbelievably, the car is reporting I have 28% battery left with an estimated 87 miles of range.
That, ladies and gentleman, is a total range of nearly 304 miles. I am astonished. Perfect conditions, true, and I was trying to get a decent range, but that's way beyond what I expected.
I sort of feel around the 70mph mark is a sweet spot. I did a short stint at 75 and noticed the range dropping more quickly. Same thing if you have a little fun with both motors. (I'm sure if I was near the Autobahn and not in the nanny state UK I could rip through the battery in an hour, hour-and-half. But it would be lots of fun!)
The car itself behaved well. I used the ACC and lane keeping for a lot of the journey, so was gliding up and down the M5, with just my hand resting on the wheel.
However, the auto lane changing is really hit and miss; for a while I didn't even think my car had it. To make it work you need completely clear lanes, then it gently drifts over as you indicate. However it takes too long, and on several occasions it didn't read the solid white line along the hard shoulder, and I ended up bouncing along the rumble strip. It's a fun gadget, but I don't think I'll be using it much unless they patch it, make it quicker to operate and a bit smarter/more responsive.
However, all in all, I bloody love this thing. It's the fastest, most technologically advanced, quietest car I've ever owned. And with the range it appears to have, who needs an E40?