Which ability for Lycanroc-Midnight is better for a Moon playthrough?

I’m planning on playing Moon again, and I want to use Lycanroc-Midnight in my team. I wanted to ask, though, whether Keen Eye or Vital Spirit is better. Keen Eye can be helpful for Pokémon that use evasion raising or accuracy dropping moves, like Double Team and Sand-Attack, but Vital Spirit prevents sleep for Lycanroc completely. Both seem pretty situational, but I would like to know which is slightly better.