Well a couple of guys at my club have just started playing orcs and its pretty scary. Don't quote me though, not a 40k player and just played a couple of games.
Something like this:
6-9 Killer Kans (the smaller ones) out front to take the punishment.
3+ units of 30 Orcs to just swamp everything. Can only kill so much.
1-2 units of Lootas. Lots of fire power there.
Some grots to spread out and stop deepstriking/outflanking. Really Annoying when you're trying to play daemons
Take it as you will, but it seems pretty damn effective to me.
Don't whine about the comp system at tournaments, even if there isn't one. Bring an army that's appropriate for the comp system.