Popular technology columnist Walt Mossberg has written an interesting article today about the overwhelming success of Apple’s iPod, and how some recently released “clones” stack up against the most popular portable music player on the market. Specifically, Mossberg looks at the Dell DJ, from Dell, and the Samsung Napster YP-910GS, from Samsung. While he still prefers the iPod overall, he says that “for the first time, Apple has real competition in this market. I expect the Dell, and possibly even the Samsung, to steal sales from the iPod in a way that no previous competitor has been able to do.”