It depends. If they're used for good, quality roleplay purposes and not for stirring up mischief and confusion on the forums, I'd be more in favor of doubles. But at this point, doubles have lost their flair with me. They could be cool, but none of the recent ones have really set the bar as a good double.
I do, however, like doubles such as @Corin_Dancepiper/@Lucy_Ambergear, @Milady_Despark, @Salazar_Brokennight, and @Fae_Depenny/ cough @Tempest_Vonpride cough, just to name a few, haha. I think showing doubles for who they are through quality roleplay rather than trying to popularize them through unnecessary ambiguity and obscurity is more enjoyable than making people try to guess who they are and leading them down rabbit trails that never seem to end. I don't mind if they don't want to tell people who they are right away because of roleplay reasons, but when they prolong it out too long and lead people down rabbit trails, the prospect of doubles becomes dull.