Frankly, I love my Multi-Functional Steering Wheel. I do have the phone, Bose, and Nav options but:

1) IMHO it looks better than the standard wheel (just my opinion!)
2) Turning volumes down quickly is much easier than taking your eyes off the road (for which I do FAR too often already given all the button the 997 has on its console). This is also great for quickly adjusting the volume of the Nav lady's voice when it comes on.
3) Zooming in and out on the Sat Nav map quickly.
4) Great when coming into your drive at night and seeing the cool illuminated buttons haze around as you turn the wheel quickly

NOTE: For us in the UK with Right Hand Drive, the 997's centre console is the same way around than for LHR cars. The ergonomics of the setup on the console is therefore designed in mind of the driver being on the left of the console. Therefore in the UK, we have to 'reach' a lot more for common buttons than the rest of the world have to. Having the Multi-Functional Steering Wheel to take away some of that reaching (and therefore taking eyes off the road) is a HUGE plus in my book, and makes driving much safer.