The F Pace is a more engaging car to drive - steering is more accurate, turn in sharper, body control very well resolved and much lighter with less roll and inertia during manoeuvers. It is also faster (feels considerably faster than the official time differences), so far is proving to be more economical and specification wise is better value when specified like for like.
Personally, I think the RRS interior (other than the dated infotainment) is a nicer envornment, build quality is much better, interior noise is lower and the car is supremely comfortable. On the downsides, the extra weight goes against the sharpness of the handling, the steering feels a little detatched but is acurate, performace is brisk rather than fast and economy is around 4 - 5 mpg lower.
I chose the F Pace over the RRS because of the better handling / performance, and because theRRS seems to be the default choice of many friends. If the performance element was less important than the comfort element, then I would have gone RRS.