In order to comply with UE rules and general green policy BMW went away from solvent based paints a few years ago, this is an issue as corrosion resistance is not as good. Some 1200's have had issues with the altenator belt cover area coroding, but I havent. cylenders heads dont corrode, but they do get scratched in a fall, best to protech with covers and crash bars.
In the past BMW has definately been a quality product, it still is but Honda are definately up there too. BMW is still well ahead of the other jap brands though, at least from what I've seen. Difficult to beat an onda...