The samsung technique may well introduce more lag since it's involves processing two images to form a third intermediate image. Anything that involves any sort of processing by the screen is always going to introduce lag. It may well reduce the appearance of ghosting though. The other 'black frames' solution shouldn't introduce extra lag though.
Can I ask what the quickest LCD you've seen running is? It's just the implication of your first post is that you think all LCDs still ghost badly, whereas on anything that's 8 ms GTG or less the ghosting isn't noticeable during normal gaming. My Dell 2007WFP does a fine job in fast gaming, and there's screens out there comfortably quick than my Dell. There is a little bit of motion-blur-type effect on fast moving objects but that's all, and if you don't look for it you don't see it. The lag is minimal too, not enough to notice, even during UT2004 matches.
I notice from your other thread you are thinking of ordering the 2407. I can't remember anyone here ever saying it ghosted noticeably, and I can remember from tests some website did that it didn't have bad lag. Unless you're very sensitive to blur/lag I think you'll be happy with it.