Have you driven the cars? They feel quite different. Any personal preferences between them?
The current 5 feels too large and heavy to me personally, but it might have more back seat room than the Jaguar. I was impressed by the power and fuel economy of the diesel.
My main reservation with the Jaguar, which can be more engaging than the BMW, is that a much improved, all-aluminum second-generation XF arrives in the fourth quarter of this year. If you can wait that long, it could be a fantastic car. But it will then also be an all-new Jaguar in its first year.
I assume you've ruled out the A6, already available as an updated 2016. (If some 2015s are left over, there could be deals.)
The Infiniti Q70 might also be worth considering. For 2015 they added a long wheelbase model. The view forward is an acquired taste--the A-pillar is unusually far inboard. Gives the car a bit of a sports car feel, but also impacts perceived roominess. Also the chassis isn't as well-tuned as the others.
I don't know if you're open to a Hyundai, but the second-generation Genesis is a surprisingly good car, has been very reliable so far in our survey, and will cost far less than the others. The main downside: its V6 engine isn't as powerful or as efficient as the boosted engines in the Jaguar and BMW.