There is no evidence that all polybutylene pipes crack in time. Failures occurred quickly in tubing that was uncured at the factory. The failures experienced in the south were due to improper clamping used to hold the tubing to the fittings. But a fitting method that takes a great deal of care is probably too hard for many, so the use of the material should be ended. I still have pieces working fine in many applications. The material was approved for drinking water by all codes, so I wouldn’t worry about it in drinking water lines.
But you still might have some legitimate claims. There is some indication, though not evidence, that chlorine may accelerate wear in hot water pipes.
Informative sites are:
http://homerepair.about.com/homegarden/homerepair/library/blpolybp.htm
http://www.tlpj.org/tlpjf/alert.htm