A couple of years ago, while staying at my friend Helen’s apartment in Brooklyn, I made an upsetting discovery: The stupid-expensive Dyson Supersonic Hair Dryer is remarkably good.My hair, which is long, straight, and relatively thick, doesn’t require specialty products to look okay. So in 2016, when the Supersonic blew onto the scene to breathless reviews of its game-changing status, I didn’t think much of it.The price tag (currently around $430 with attachments) was almost triple what I’d consider paying for a blow dryer. (And it’s about $350 more than the price of the Rusk W8less, the top pick in our guide to the best hair dryers, which is also a staff favorite.)