well, by stable i mean it isn't full of bugs, and doesn't crash all the time. if they are all stable by that definition, then it was my mistake to think some weren't.
Most big companies wait until SP5 or later. SP's this high will still have bugs, but they tend to be pretty obscure by that time and your likely hood of running into one becomes less. Of course, since we wait until then to start testing, we don't find any of our bugs until then either