i own the ath-m50s (straight cable, m50 is coiled cable).
i've found sound leakage to be minimal.
i've heard that they lack good mids and have good highs and lows but until i read about it i never thought about it much. the sound quality although hyped up is definitely good for the price.
another good feature is the low resistance (35ohm if i remember) which means you do not need a seperate amp (but you can use one). this makes it great for on the go listening on phones, mp3 players, laptops, etcetera.
you should be able to get them online for between $90-180 depending on where you buy. sweetwater sells replacement ear pads for about $20 and i would definitely suggest picking some up as sweat will harden the pads and eventually cause them to crack.
my pair is about a year old and while the pads are hardened they arent cracked since i take care of them. i need to get myself a replacement pair of muffs but other than that nothing went wrong.