@ Itachi Namikaze: "Back to the thread though, you do know kamui just teleports within their world. It isn't like he would be killed by being transported somewhere else. The most that could be had from that is a draw because they aren't near each other anymore. Seriously kakashi used kamui on Deidara's arm and then Kakuzu found it and reattached it. It doesn't go to some alternate dimension like Madara's jutsu." and "Um I highly doubt that kakashi knows more jutsu than Orochimaru. He was on a quest to learn every jutsu in the world. And actually I'm almost positive Oro is faster than kakashi, and Oro is a genius both medically and in the ninja skills. He performed experiments on people and created Yamato and a bunch of other stuff long before Kabuto was around."
I do not remember if the manga states where Kumi takes the teleported things. But kakashi's MS is a one shot thing. If he missed then he is done for. If he hits then it would take all of his Chakara but im sure that he could get Oro's entire body.
Without relying on his MS Kakashi has more nin-jitsu then Oro. Because the Third Hokage perminatly sealed away his Spirtal chakara (arms) which means that he has lost the ability to mold chakara. This is why he relies on tie-jitsu and Oral techinques. In addition Kabuto was able to put that seal on Oro's physical arms so in times of great need he could summon the Raishimo gates to portect him still but, he even needs Kabuto to summon snakes and Edo Tensi for him.
Even so Oro has more Chakara then Kakashi, is as smart as Kakashi, is physically stronger then kakashi, and that ability to fully regenerate would be a pain to get around. Then if Oro got serious then he could go into that great snake form (not on the verge of death) could pose a real problem to kakashi.
On Kakashi's advantages he is faster then Oro, many more Nin-jitsu tecniques, can rely on hit and run tatics with clones/trap clones, has all of the advantages of the sharingun, can preform sealing jitsu and now has the Beheader sword from the Hidden mist--- Could possibally preform the technique that made his dad Kahona's white fang???
In short I think it would not be so one sided as everyone thinks it would be but the odds are in Oro's favor, simply because of the sheer physical stamina of Oro; which seems to be Kakashi's weakness.