I've had both the 6 cyl gas and diesel F15 as loaners.
I echo the opinions on the steering - too light, lack of feedback - just didn't feel "connected". I also didn't like the brakes - BMW switched to a low dust brake compound at the expense of initial bite and feedback.
It looks "OK" to me, but I prefer the more aggressive look of the E70. I like the interior, with the major exception of the nav screen - I prefer the more integrated look on the E70.
As for the drivetrain, the gas version was OK, but I thought the diesel combined with the 8-speed transmission was excellent, and a big improvement over my diesel E70. The F15 diesel/8-speed in the E70 would be a winner IMHO.