Just had my first 6v6 wifi battle with this thing (previously only did 3v3) and oh my god, this bird. If the opponent's counters are neutralized or if they don't have anything to check it like Stealth Rock, this thing owns. As said before, I run 4HP/252Atk/252Spe with Sky Plate and Brave Bird/Flare Blitz/Roost/U-Turn because I'm a troll, but even though it's not necessarily the best EV spread, it does its job beautifully. Seriously, if you know their bulky counters are gone, not even resists will save you from this bird of doom.
...I think I might have to stick SR or have two counters for this thing from now on. It's goddamn scary.
Rotom-Wash is an excellent counter. I've been putting EVs into HP and DEF just to take care of Talonflame.