Hello Kevin,
How long are you planning to keep this vehicle? if you are going to keep it for another 4 - 6 years then "I" would seriously consider it only because the more miles you put on this awesome SUV, the bigger your chances of a major repair. If your intentions are to trade it in in the near future (1 - 2 YEARS) then "I" would take my chance and not get the extended warranty.
I would recommend in contacting two or three Land Rover dealerships in your area and talk to the service manager about the most common problems that plague this SUV. Also, ask what the worst example of a costly repair and how often have they seen it. As you are communicating with these managers ask them how the aftermarket warranties work and if they are better or worse ones. They will give you the nitty gritty on all of this stuff. If they don't then call another dealership and get your answers.
Another way to ask yourself if you should buy an extended warranty would be like this.... If you were looking to buy a used Range Rover Sport with 40,000 miles on it would you pay extra to have it certified or would you take your chance and roll the dice?
Hope this helps with your decision.
Take care and have fun!!!