Zone PvP - Nothing. I only use those zones for the temp powers you can get there
Arena PvP - Being able to customize the settings i.e. turning of DR, travel suppression, pre match buff periods are good to get on "equal" ground to start off.
As with a majority I enjoyed PvP more pre I13 but I still see potential for it be a major factor again in the game. With a few tweaks and some incentive to PvP (other than PvP IOs since you can get those in arena) zone PvP could make a comeback like it did when Recluse's Victory was released. That was probably the most fun i had in PvP.
A Praetorian PvP zone would be interesting. Of course for maximum playability it would require the Praetorian zones to go to 40-50 for end game quality PvP. I know this would require a MASSIVE content implementation but it would be something to aim for in the future.
