Choose one. If you control a commander as you cast this spell, you may choose both instead.
• Creatures you control gain flying, vigilance, and double strike until end of turn.
• Creatures you control gain lifelink, indestructible, and protection from each color until end of turn.
Akroma's Will is one of white's best finishers and the gold standard for go-wide payoffs. Since you almost always control your commander, you reliably get both modes: flying, vigilance, double strike, lifelink, indestructible, and protection from all colors. That's a board-wide alpha strike that connects through blockers, swings for double damage, gains you a pile of life, and laughs at board wipes and combat tricks all at once.
Who wants it: any creature-heavy white deck — tokens (Krenko-style but white, like Adeline or Kykar), aggressive humans/soldiers, +1/+1 counters, or any go-wide commander aiming to close games in one turn. The protection from each color also makes it a strong defensive trick: cast it in response to a wrath or targeted removal to protect your team.
When to skip it: decks with few or no creatures — control, spellslinger, or artifact-combo builds get little here. It's a payoff card, so you need a board to pay off. With an empty field, it's a dead draw.