Well, a roughly two and a half hour horde queue time, and I am assuming insta queues for alliance.
I have had something like an 80% win rate, which if we assume insta-queues for Ally, roughly 30 minute games, (and this part could be way off, but) roughly equal win/loss rates for Alliance would be about 1 win ever 5 games, or 2 every 10.
This was on the Eastern battlegroup though, when it existed. My Alliance are on the Western battlegroup, and I have not queued AV as Alliance since the first week of release.