Now that I'm an owner I look for them, and itsky is right, you don't see many around here.
In the past month I have only seen 2; An SSB Roadster in Castle Rock from 600 yards, making a turn, and an SSB or graphite coupe going the opposite direction on C-470. (too quick to tell the color for sure.)

I've been known to follow an interesting car to talk to it's driver before, though.
And I'm actively looking for other XFs on the road, so I guess I have some of that obsession too.