Well your choices are sort of limited as far as readily or locally available. Basically you have M1 0W-40, Castrol Syntec 0W-30 or "German Castrol" or "GC" for short, and then the BMW dealer oil, a Castrol-blended synthetic 5W-30 product. I would use any of the 3 with confidence, but change the oil somewhat before the oil life monitor indicates to, just to be on the safe side. The GC is usually only carried by AutoZone or PepBoys. M1 0W-40 is probably the most widely available and comes in qts only for the retail market. (no money-saving jugs) Once out of warranty, there are many oils that would work fine in place of LL-01 oils, if changed in time and if the oil has sufficient HTHS (hot viscosity).
Are there better oils than these few? Perhaps, but will probably cost more overall and be harder to find. What is your application?