A buddy of mine offered to sell me his Naga because he's getting the WoW mouse, and another friend is mailing me his Naga because he says he prefers the WoW mouse. Really odd, since I would go for the Naga in a heart beat. The latter was complaining how the Naga felt weird getting used to.
Having heard what seems to be the most common issue with the Naga, it would be what I'd still pick between the two. For playing WoW anyway.