I had a Paladin that insisted on sparring with members of the party, especially when someone new joined. I found that damage is high enough and HP's low enough that the initiative roll could often determine the entire battle. Also, as a Paladin I was often at a distinct advantage. Although my mark was useless, I could heal myself as a minor action, and did off-striker damage. With the role system, some classes are just going to be innately better at pvp than others. I wouldn't make it a regular thing, if you are considering trying it.
Jay