I have HID's on my '08 Mazdaspeed 3 and they're fantastic. Clean white light with a sharp cut-off. I drove my wife's new '16 CX-5 with LED's for the first time last night. My first impression was that there's not an obvious difference between HID's and LED's, certainly not like going from halogen lights
The cutoff does not seem to be as sharp as the HID's and there's a little halo effect at the cutoff point. Need more seat time for a better evaluation.
In any case, if you have an opportunity to have them (either HID's or LED's), they're a MUST HAVE. One nice thing about the CX-5 over the MS3's HID lights is that you also have them for the high beams. The MS-3 uses a halogen light for the high beam (ugh!), no bixenons on that car. IN any case, $1500 for the tech package is bargain. Take a look at what BMW charges!!
The autodimming feature is really cool. I could see that very useful on a long trip. Between that, the lane change warning system, active cruise control and smart braking control, there's not much else to do but point the steering wheel -- scary! Looking forward to a long trip in the car, so far only 500 mi on the odometer.