The Jag XK is a huuuuge improvement over the previous generation XK8. It is 300HP versus the Ferrari ~500HP, and roughly the same weight, so speed-wise the Jag is no comparison. If traveling long loooong distances the Jag would be a bit more comfortable, and gets much better fuel mileage (30mpg+).
Ferrari feels much more planted and stable, however the Jag is no slouch and is very confidence inspiring in the twisties.
I'm much more a fan of the traditional manual rather than the paddle shift auto.
Interestingly, in a straight line the Bentley will pass the Jag with little effort. In the twisties the Jag will pull away, but you'd be absolutely amazed what you can do with the Bentley when you set your mind to it.
It is a very nice fleet, each car is very different in its own way.