The only way I'd be sliding into a '14+ right now (as I have a gem '13) would be if it had Adaptive Cruise and HD. I'm holding out for a '16 with both but odds are it's my '13 until forever.
Got the Adaptive cruise control on my 16, works great but I was super disappointed to find out that it doesn't actually bring the truck to a complete stop like other manufacturers, even low-end make/models. Did quite a bit of researching before ordering the option on my custom order, tried to read into the marketing hyped option naming conventions, asked the sales guides and service people but no one could give me a yes or no answer. Finally, looked at the option' description available on the top dog Range Rover, compared the name of the option to what was listed in an LR4 options' list, compared the pricing (same for both models), and misunderstood that just because the option name and the pricing was the same on both Range Rover and LR4 models, the functionality would be the same too. And of course it turned it out to be not the case. It was like as if all the literature and description and the naming conventions for LR4 were purposefully designed to confuse the hell out of the buyer.
Was super mad that I paid the same amount of money for this option as in a FFRR but didn't get the fully functional option as available in the RR. Talked to an LR exec rep at the LA auto show but it was too late by then and I was already driving the truck.
In an emergency type of situation it will definitely brake the truck hard and will bring it to a crawling speed but wouldn't bring it to a full stop and a message comes on the dash saying the driver needs to intervene, etc. and then you have to take over and apply the brake or else you may end up kissing the car up front.
One good thing I noticed with this option that with the cruise control set to a specific speed, say 65 mph, if you begin to get on a downhill grade etc, the system will not only decelerate (just like any normal non-adaptive cruise control system would) but it will use the braking if necessary to maintain that 65 mph and won't let the truck get past that speed mark like you normally would if the grade was steep enough. But I personally usually turn the ACC off in a situation like this and start using engine braking or lightly tap the brakes on an off as needed as I don't really know how much wear and tear the ACC is putting on the brake pads to maintain a set speed going downhill grade, fearing that overly priced brake pads replacement job at a stealership.
One thing I have noticed that if the system senses an emergency, the damn thing brakes really, really hard, prolly harder than a human can apply the foot force on the brake pedal, and in a great manner as far as brake force distribution cuz you can feel the truck' rear end being pushed down vertically on the pavement vs having a total nose-dive.