First strike is a marginal ability that requires blocking to begin with (on one side or the other) and requires that you have more power than the opponent has toughness to even matter (give or take the stray dealing of first strike damage followed by a removal spell)
Both methods are great and, above all, fun
This Boros phoenix pounds away at opposing life totals on its own before you consider support from cards like Mondrak, Glory Dominus, Purphoros, God of the Forge, or Grateful Apparition
Its value dropped a bit for Commander after the tuck rule left (you could tutor up your leader if tucked into your library) but its still a strong tutor for a lot of decks and board states
Strong appeal for Eldrazi fans
Take the -1/-1 counters off your persist creatures and hand them to an opponent, or shift a lifelink counter from Dust Animus onto your Aetherflux Reservoir