peter
2004 330i ZHP
2005 330iT ZHP
2010 328iT M Sport
Mine weren't bent in that way. The previous owner must have smacked them against a curb pretty badly, probably while going sideways, because the two wheels that were bent to holy hell were the two that had curb rash on them. With that kind of force, you'll bend any kind of wheel, regardless of how it's made.
As far as regular driving goes, no bends whatsoever. The wheels balance out perfectly after they got straightened. We'll find out for sure at my next tire change whether I've accumulated any bends since then, but so far there have been no vibrations whatsoever from the wheels.
No wheel is immune to bends, just that some are stronger than others. I never question the quality of BBS wheels.