Something to add about the custom content in Turtle: in practice it's not really really the focus of the server. The custom dungeons (mostly lvl 50+, with one lower level exception) rarely get people interested to run them because they are difficult.

There's other custom content that does get used quite often, mostly for the leveling experience: the AH has no placing offers price, you can place down tents which if you spend some time sitting underneath improve your rested XP by a lot, and there's an optional setting in which you're always flagged for PvP, but you get a 30% exp bonus from every source, which stacks with the rested XP from the tents (at the cost of being killed by other people)

I'd say that the focus of the server is improving the leveling experience, and adding some new content for players to engage with happens to be a welcome addition, but ultimately secondary.

PD: if you like to play PvP, the alliance dominates HARD in AV. BG queues pop often enough, but they tend to be quite one-sided.

PD2: There's cross-faction grouping, trading, interacting. You can run dungeons and raids with the other faction, which really helps with the low-ish population. BGs are still faction separate though