>>713353731They're fairly different at this point. In essence, Epoch is vanilla content running on the WotLK patch for stability's sake but with BC talents for balance and fun's sake. Plus some minor tweaks here and there. Sounds like a decent philosophy, if you ask me.
Turtle on the other hand is trying to evolve vanilla in a direction that their dev team believes was more consistent with Blizzard circa 2004-ish. They've added new races, new dungeons, and heavily tweaked some skills and talents (Lightwell is gone and forgotten, thank fuck). They're currently in the process of making a UE5-based client that can switch between classic graphics and shiny new ones they're making.
Turtle gets some flack for having an overly-sensitive/"woke" mod team, but I've never chafed against that personally. I still play it from time to time and am also interested to check out Epoch when it launches.