Well, I got it. The good news, it really works. The bad news, $1300 installed.
The core functions are FCW (forward collision warning- sounds alert when you get too close to car in front, time to collision is user selectable) and LDW (lane departure warning- alert when you drift out of your lane, not user adjustable).
FCW- in the 48 hrs I have been using it, I already love it. I didn't realize how much "background" mental energy I was using to keep a safe distance to the car in front of me, especially at night until I started using this. On busy highways judging if the car in front of me has slowed down, especially if their brake lights don't go on, is difficult, especially at night. I find driving in these situations now much more relaxing, since, if the car in front slows, I get an alert, and I just let off the "gas" (accelerator) pedal, and I find I am no longer mentally going "oops that car is now closer than I thought." System gives a louder and more urgent alert if the distance between me and the car in front is decreasing at more dangerous rate (i.e. I was tuning the radio while the car in front was rapidly decelerating). Works well and reliably, day or night.
LDW- works well in most, but not all situations. Specifically, if the lane markings are faded or reflections from rain at night obscure the lane markings, the system will not pick up the lanes. Mostly works fine. Clearly helps if I'm a bit distracted (talking to passenger, getting sleepy, etc). This function took me a trip back to the installer to get it adjusted to my taste. The factory default is for the alert to sound when the tires cross the line, I wanted the system to alert me when the tires were still 12" inside the line. The installer didn't know how to do this adjustment and it took a couple of calls to Mobileye tech support for him to get it right.
Other functions:
Pedestrian/Bicycle warning: Works, but only in daytime, and seems to me I would have to be nearly dead for the warning to be actually useful. I haven't had it alarm so far, so I really don't know how good it is. Obviously would be MUCH more useful if it worked at night.
Automatic HiBeam control: works very well, and I didn't realize how nice this is, driving around my neighborhood at night, the beams go up and down depending on location of street lights and presence of other cars. Does make vision better with NO input from me, and, I assume, safer for those situations in which I previously left my high beams on and a car was approaching me in the opposite lane.
Automatic speed limit indication: works poorly, actually reads street speed limit signs, but frequently picks up a sign for temporary slow limit, but then doesn't realize that the school zone or what ever has ended. Frequently misses speed limit signs that are off to the side or partially obscured by trees, etc. If you want a speeding alert, GPS based ones work much better. I turned this function off. Annoying.
Anyway, I am absolutely positive it will decrease my chance of an accident. I am planning on having the system installed in my wife's Leaf and my 19yo daughter's Ford Escape (she texts while driving, even though she knows its dangerous) in the next few weeks. If found a different installer who will do it for $1100. I live in silicon valley, if you live in a less expensive part of the world it will be a little less to install. Took 6 hours total for initial install (installer estimated 5 hours, but was also working on other cars during this time). Took 4 hours more for re-calibration of LDW, but only because installer didn't know how to do the adjustment to fix this, a better trained installer could easily do it in 45 min.