Superb bass extension without boost which fits me perfectly, use them primarily to listen to music and gaming, for gaming I use the reveal vst plugin which makes them sound abit easier and with a little bass boost, for music I like them better without.
Not hard to drive but not as easy as the 20 Ohms would suggest and an amplifier will improve the sound even if it doesn't sound bad from either my iphone or macbook directly they surley sounds fuller, clearer and meatier with an amp.
Also they are heavy and have quite the clamping force for wich i deducted one star for comfort.
They are in no means uncomfortable and I have no problems waering them hours on end but you will never forget that you are wearing headphones.