Have had this vehicle 4 months now, so far very good experience. My second BMW, both purchased new, and thus far more reliable that previous (X5); really no problems that have required dealer visit (after a few items that were resolved at 1200 mile oil change). Great stealth car - looks much like "normal" 5 series to most, but really goes when challenged. Good daily driver, with room for luggage and 4 adults, and makes to / from work or airport almost fun. Sometimes tough to keep under speed limit - suggest a good radar detector, and set the speed limit warning because easy to go fast (set mine at 85). Given other alternatives available today, would buy another if this one disappeared.
Plenty of power in "normal" mode @ 400hp; when push the M button the real fun begins. HU display is better than expected, same for enhanced stereo (car had both vs. what I would have ordered). Handling and brakes solid & firm. SMG better than the auto press indicates - but takes time to master.
Mileage, of course. Or at least put a bigger fuel tank in it (this was a serious consideration for CLS 63AMG); real pain to fill-up so often. Also would be nice to have even a mini-spare vs. seal-kit for potential flat tire. Improve SMG (in the works for next model?), but still better than 6spd.