One question that many constructed players are asking themselves is whether this card will be more viable than Lyra Dawnbringer.
Some players don't like that it has only four toughness, which makes it vulnerable to something as simple as Lava Coil. On the other hand, it not only adds life to your health pool, but it literally prevents you from losing a game.
Taking all this into account may mean that you want to run one copy of Angel of Grace alongside a copy of Lyra in your deck, and you may want a couple more in the sideboard. Both Modern and Standard players will find themselves in situations where they will really need protection from losing the game, and Angel of Grace will be able to provide exactly that.