M,
Got any links to those reviews??
Did it just get shipped bad, or did it go bad over time??
I can't see how it would crack unless not drained in the winter or sudden freeze..
They seem to me to be pretty beefy.. At my house I have the Pentair CCP 520.. It is about 12 years old and working fine.. but, if it went bad tomorrow, I'd replace it with the Waterway.
Thanks,
Jim R.