In addition to what has already been mentioned, Argh can also beat a common stallbreaker, CM/Rest/Surf/Ice Beam Kyogre with help from Blissey. Switch Blissey as your initial counter (once you know it isnt specs) and let it cm up to +4 as you wall it. Once it is +4 switch to Argh and laugh at its Surfs and Ice Beams. With Punishment (200 BP against +4/+4 Kyogre), you can 3HKO it (meaning Rest can't stall you out: You hit it once when it rests and twice while its asleep), as well as hitting things like Mewtwo, Lati@s, and Deoxys-A super-effectively. I run Punishment over Waterfall on the current Standard set, especially since Groudon's Sun weakens Waterfall and Brick Break/Ice Punch cover most everything already. Being a solid Darkrai check is also something stall really needed. The only thing you have to worry about is Wobbuffet allowing Darkrai to set up on you.
I HAVE WON THE BET