In-game: Neither. Brute force your way through everything. You rarely need to set up in-game, and Choice items in-game are a complete waste.
Battle Tree: Swords Dance + Focus Sash. Choice Band may make your attacks hit harder, but so does Swords Dance. Choice Band leaves you open to being OHKOed, while Focus Sash ensures at least one Swords Dance.
Online battles: See Battle Tree.
Battle Tower: Again, use Swords Dance and Focus Sash. Absol is quite frail, and Focus Sash helps it stick around one more turn. It's certainly a better choice than Choice Band.
As you can see, I would opt for Swords Dance in almost every scenario. Absol is simply too frail to pull off Choice Band succesfully.
Hope I helped!