From what I can determine, the design change Scrod points out was made for the 2013 Lavender edition of the Big Block. If the posts complaining about breakage predate that or the owners mention that they had a pre-2013 Big Block, I'd say it's safe to assume the problem was addressed and the new design is more durable.

Keep in mind too, that while there may be a lot of complaints about frame breakage in that thread, it's still a small percentage of the total number of Big Blocks out there. People who feel they've been wronged or ripped off tend to be louder than the satisfied customers, and can make themselves seem like they're part of a larger group than they really are. Folks are quick to ***** about faulty products, but they don't always make much effort to speak up when they're happy.

Bottom line - I don't think there's any reason to fear the Big Block as a poorly made death trap in waiting. It's not a Viscount with a death fork, thankfully