1) How many additional locations/waypoints/favorites (every company has own name for it) can be added by user.
2)How well does the bluetooth/voice recognition work?
3)Is the nav. worth it?

I don't have the voice recognition, so I can't attest to that, but I find the current nav to be fairly good. There are some areas on the map that are not well developed. Several forum members have commented on missing areas in smaller cities. You can have 2 stopovers and one final destination for any given destination. The computer saves your previous destinations and you can save them as a favorite as well. I believe I saw 5 in my "last used locations" area. I have found the chosen routes to be pretty good and intuitive.

As to whether its worth it, that is a personal question that only you can answer. Some people would say nothing is worth $1500, others say in the setting of the car price, that its a pittance. I say its pretty good, but not something I can't live without. I will certainly use it at times, and during those times, I will be happy I don't have to keep slowing down or pulling over to check the map.

In Europe you can't sell a used car without it in the A6 segment ... even the smallest engine in the A6 (the 2.0 TDI with 140hp) has an installation rate of over 50% in Europe ...

True, America is not so crowded with streets, but I like having one just for the case I need one. I hate regular maps ;)

can the nav hold and how many waypoints per route?

5 and 2.

Sorry, but I find that to be unbelievable! My Garmin St. Pilot can hold 500 additonal waypoints and 10 destinations from start to finish. If this is correct(it would really, really suck!!!), then I will buy the Sony Vaio u50/70 and install in car.

Anybody have experience with the u50/70?