Originally Posted by treechunk
I've talked with several people who have had the splined adapter get worn 'cuz it's tough to make the tolerances tight enough to really stand up to street use. Basically, eventually the cog's splines and the carrier's splines didn't fit super tight, and the cog rocked back and forth, which just made the whole issue worse. I'd recommend against it. If you're changing your gear that often, a flip-flop might be a better option.
I will second this - I've heard 3 accounts of it working and becoming loose and the cog "feeling like it's slipping, just a little bit". Ugh.
They seem like decent hubs but responses (aside from this thread) seem mixed.
As for double-sided - I love double-sided hubs. Costs a bit more but it's worth it. Changing cogs out is a hassle. I ride street and track so that's necessary for me. I have different wheelsets but I still like double-sided hubs.