SoA/ToB full simultaneous release. Closed Beta Tests.
This one. Though I'll admit I'm not a big fan of ToB, I have played it many times. A Mod doesn't feel... "complete" without a ToB portion. I don't mind waiting a while longer for the ToB portion of a Mod, providing it gets worked on. I'd probably play through SoA first, and then wait for ToB, where I play both SoA and ToB, especially if SoA has new/more content than before, and/or bugfixes.
Bugs annoy me more than anything else in Mods (especially my own Mods. Grrr...), so I'd definately suggest a closed beta test with handpicked testers.