First thing you're going to notice with these cans is, of course, the bass. When properly amp'd, these things almost pop off your head. I haven't heard the JVC sz2000 or the Sony XB1000, but these have the most bass I've experienced so far. Some cans have punch but no sub, others have sub but lack punch. The ATH-WS99 has both. The highs are surprisingly clear. The mids are recessed and veiled. I have no problems with build quality and comfort.
 
Side note: I got these off of Sears website for $34 bucks with free shipping, refurbished from the factory. A freaking steal if you ask me. I thought it was too good to be true, until they came in the mail. They list for $250. I've seen them on Amazon for less than $150. If I paid $250 for these I'd probably be unhappy. They aren't bad headphones at all. But the lack of clarity in the mids doesn't make them sound like 250 dollar headphones. 

For less than $200 you won't find a better pair of headphones for studio use. I wouldn't recommend these to anyone who isn't going to be using them in a studio. You can't really take them with you and there's much more "fun" hi-fi headphones for home use. But if you need a cheaper super flat pair of cans to check mixes and/or monitor sound, this is your choice. They do lack a bit of punch so placing kick drums is a bit of trial and error in these things. At higher volume sub-bass tones rattle them up a bit in a bad way. These are the reasons I'm not giving 5 stars. Other than that, they're a great buy.