I formerly have driven BMW's for the past decade. The price on the new 7-Series has gotten a little pricey, so I looked at alternatives. For the money, I could not have found a better drive. I tested the V8 for a week then the V6. There is truly NO noticable difference in the performance, and since the majority of my driving is in the city, I would highly recommend the STS V6. Fully optioned it is priced closely to the base V8.
The voice command feature and the hands free calling (bluetooth).
The GPS system is only available when you are not driving, which can be somewhat of a pain if you truly need quick assistance and have a passenger who can enter data into the system. I would like to see some override for this feature.