I last looked at Hey about a year ago and it seemed pretty snappy even from the the wrong side of the Pacific. The page architecture impressed me specifically ... things like, applying progressive enhancement to a details/summary/anchor element trifecta for a contextual menu overlay, and if you disabled Javascript or assets didn't load or whatever, it gracefully fell back to loading the menu content in a simple layout. There are a bunch of other well-considered uses of the Web APIs in there. I recall that practically all their client code was unobfuscated and source mapped, too, if you wanna take a look. I'm no fan of DHH and have no interest in boning up on his drama of the week, but it seemed to me that 37signals got it right this time.