Just being the devil's advocate for Beat Up.
I never really liked Beat Up... until I saw being used in Competative Play.
It can break through Focus Sashes and Sturdy with ease. With max Attack at Level 100, each hit has a power of 36, which is pretty good for a Multi-Hit move. With STAB, 54. Hitting 6 times, the combined power is 324 if all member are alive and don't have a non-volatile status like Burn, Freeze, etc.
One downfall: it cannot be boosted by moves like Swords Dance. But, it can be boosted by Items like Muscle Band, Choice Band, etc.