lol....wtf is a double lifetime warranty? If you die playing a video game you can pass the warranty onto your kids?
Warranty is a pretty big concern if you're dumping $400 into a video card. With components running as fast and hot as they do, there's a decent chance for them to die, and if they do, a company that's easy to RMA with makes a big difference.
Anyways, back to the OP's original question. I don't think these parts are binned at all, the Superclocked are simply replacing the originals (the original black PCB GTS are getting hard to find) and the new clocks are simply taking advantage of the OC'ing overhead the G80's have always had. If you look around, there's few, if any original GTS and GTX running slower than 600/900, lots are hitting 650/1000+.
The one difference that you can't make up between a Superclocked and Original even if they end up OC'ing to the same speeds is the Shader Core OC. As of now, there's no way to OC the Shader Core without flashing the BIOS and thereby, voiding your warranty. The Shader Core on the Superclocked cards runs 100-150MHz faster, usually the same speed as an original GTX. Keep in mind though, the Shader Core speed difference doesn't produce nearly the results in performance as a straight increase to core or memory clocks. I think AT did a comparison in that OCZ 8800GTX review and the difference wasn't linear, maybe 20-50% improvement relative to Shader Core increase.
Personally I'd go with the Superclocked at this point if its only $20-30 more. They're newer parts even if they're not binned, so you'll be taking advantage of any incremental overhead achieved with newer parts and better core yields. Plus you get the faster Shader Core, even though its not a huge impact, its still faster.