AP or low population server benefits? For me the low pop server option is better, as things currently stand.
Playing state side: I live in Europe and play on a shitty laptop, so the additional latency I'd get playing on a US server would be unacceptable to me.
General resources: When it comes to farming things (which us true f2p's have to do), I want the process to be as quick and painless as possible, so a low pop server with minimal competition serves me well.
AGM: It's not something I need, but as a completionist it's something I want. As previously stated, a quiet server can take a lot of the pain away, and I'm all for that. As for the QQ regarding AGM, lol really? Skill > AGM, so if it's an issue, L2P
Community, premades, etc: The main reason to roll AP it seems, but personally such benefits are not high on my list of priorities. I find making friends on a quiet server quite easy, and when I bg, there are almost always regulars who are both skilled and friendly. That's more than enough community for me. As for premades/arenas, I'm not that fussed, and can live without. I'm also going to be brutally honest and say that although most AP TI contributors seem cool, I can't help but notice that many of the trolling/epeen dipshits on TI play there too. Major turn-off.
Hmm, think that's all I have to say on the matter for the moment. Quick shout out to notable EU players (inexact spelling) - Brokendemon (pala), Redesigned (priest), Zino (warrior), Zielle (shaman), Celestsys (priest), Flipzmytoast (hunter), Darro (hunter/rogue), Cavejuice (traitorbout theie eppe)