In my community, there was a law firm that went around trying to turn issues with a couple of homes in a general class action lawsuit against the builder. The builder responded by saying if you have issues with the home (even after warranty), let us know and we'll take a look.
In all, I had some minor grievances with minor things (like a seal leaks in a double pane windows), some minor cracks in some of the exterior stucco walls,etc. In all, the builder took care of things, even though I was the second owner and approximately 8 years out of warranty.
I didn't join a class lawsuit, namely because my problems were minor, it would have taken too long to get a resolution, the lawyers would have eaten all the money, and I would have otherwise thwarted efforts by the builder to actively address the minor issues i had, not to mention that you're home would now be in public records as being one that was involved in a class action for "construction defects", whatever future buyers,appraisers,lenders interpret from that. Probably not that big of a deal, but why make something appear so serious when it's not and the builder's willing to take care of it??