I believe it is just Techron additive repackaged as BMW:

Our Fuels: Fuel Additives: Techron Concentrate Plus

The use of these additives is a never ending debate, sorta like what is the best engine oil.

I personally use a bottle of the stuff every 10,000 miles or so.

While there is little consensus on the use of additives, if there is any agreement at all, it is that Chevron Techron is the preferred additive, if you are going to use one.