my understanding is that, although the s3x has its origins in the 5speed, there are some very notable differences. One of these differences is the "neutral" stuff mentioned already in this thread, found in older SA IGHs, and bemoaned to no end by the inimitable Jobst Brandt.

With the old SA fixed IGH (the asc) suffering from reliability problems, my concern would be about the s3x's long-term durability, rather than the false neutrals, which one could learn to avoid deftly in time.

I agree with Tom: the threaded AND splined interface for a hg-style cog or threaded freewheel is pure brilliance. IMHO, it's the most impressive feature of the hub.

-rob