Howdy KC,
I have the autostick on my limited. It's definitely not as responsive as the 6spd stick, however it gets better mileage (imagine that) since the six speed apparently was set up for "performance" over efficiency. While you can drive the autostick in a semi manual mode, it's not nearly the same experience.

So it all depends on how you plan to use your XF. In either configuration, the car is quite a bit of fun. Did an early morning run today on some twisty roads and had a gas. however, here in the DC area (Lots of traffic) I preferred the autostick.

Let us know which way you decide to go.