For the most part, I think they're garbage. Especially the one in the E36. It's like a chiding mother and it can really just make things more dangerous. If you lose control, you want to be able to use the engine to your advantage, and many traction control systems will CUT power to the engine, which means you won't be able to use it at all. I can't drive in the snow with it on because the tiniest bit of wheel spin means the engine will fuel cut and if im trying to take off - it'll just make the engine stall. I know there are some good traction control systems that will allow for the proper amount of wheel spin and also will not cut the fuel, but I still feel like they are still useless for people who know how to handle their vehicle.
If im driving, its one of the first things I shut off. For someone that is unexperienced or doesnt know the limits of their cars handling, I can see how it could get you out of some brain dead situations. Almost as if brain on, traction control off, brain off traction control on.