I've posed this question a couple times on various campaigns (I tend to hop around both home and guest, to get a feel for how each campaign seems to do), but I've never really gotten a fully clear answer, so I wanted to ask here.

I understand that PvP has special equipment only available through it. The vendors at the High Rock gates have given me enough info on that - in particular I'm really interested in the Covenant Medium Armor gear, partly because of its set bonuses, but also because it's the only set in the game (in the Covenant, anyway) that uses the Fighters Guild style, and that's enough to motivate me to get it. At times during my occasional PvP jaunts, I'll end up with a couple mails titled Rewards for the Worthy, which in turn rewards me with a box of random equipment. My luck on these has varied from junk that I either sell or deconstruct (shields that are lower-quality than the one I'm already using and light armor clothing tend to be the most common finds for me), to the Eight smiling on me themselves (the VR2 Covenant Jack I'm currently wearing).

What I'm curious about is how exactly these Rewards for the Worthy messages are calculated. I understand that they're apparently tied to Alliance Points, but what confuses me is what points, since that could refer to three different things: my PvP money, the experience I get to increase my PvP rank, and the points that are displayed on the Leaderboard. I'm also not sure, depending on which of the three it is, the frequency of how the mails are sent out. For a while I had assumed that it depended on my rank experience points, with the mails being handed out for every, say, fourth of the way there you got, or something like that, but then the numbers didn't start to add up.