I'm wondering this, too. To me it sounds the same. From the "bad news" section:
> CX serializes all mutative operations which means it's flat at best if the workload consists of only mutations on the sequential object. ... It also consumes larges amounts of memory and in the very unlikely worst case, may require 2x MAX_THREADS replicas of the sequential object.
That's roughly the same text I'd expect to see on an RCU implementation. (Maybe the exact number of replicas differs; I think with some RCU schemes it's GCed asynchronously and is theoretically unbounded.) At first glance, it's hard to understand what's new here. They say they used this to make "the world's first wait-free balanced binary tree". How does that description apply to this but not to RCU?