An orgasm is an orgasm is an orgasm. There is no direct physical differences in what happens to the body during orgasm that are dependant on the method. You can claim that orgasms from oral are the best, however it is just better, it is not different. Phychologically, there is probably a difference, simply because it's a lot more satisying lying on top of a naked, panting girl than it is watching relatively disgusting porno on your own in your filthy room, haha, when certain chemicals are flushed from your brain and you're sorta left thinking "what stupid creatures we are".
Emotionally there is a difference, physiologically and chemically they are identical.