we use bigfix, 400 individual sites on a private wan, 103,000 desktops and the product works real nice. It is amazing to watch it operate in real time in a huge environment and only bigfix server for the whole thing. Very robust product and the product is domain/AD agnostic it will work across all kinds of places and it is very trouble free with little management overhead and excellent techsupport. You actually deal with the developers who wrote the product etc.. instead of some moron reading from a script. But it is very rare if you will need it anyhow.