We are still running Cassandra. It's used in a more restricted way than we originally thought we'd use it, but we're following the recommendations we wrote up in linked article.
We don't use counters -- at all. (This is discussed in one of the sections.) Counters are one of the few Cassandra features that can offer you some form of value aggregation inside the data store, but we decided they weren't worth it, due to the quirks.
What do you mean by, "when it's wildly known to be a bad idea?" What are you referencing? Lots of people use counters in Redis and MongoDB for analytics, for example.
