This deck has been over performing for me as of late. After toying around with aggressive strategies, I decided that the bodies on the white creatures combined with with their utility made white the color of choice.
There are a lot of multicolor aggro decks out there with Brave Naya leading the way. I feel like sticking to one color is a close to even trade. Sure, you lose quite a bit of power but the return is quite a bit of consistency.
There's a lot of reasons to play white, but the main seller for me was its ability to punch through Caryatid and Courser. If you're talking about an aggressive strategy, you need to be able to overcome them. I've beat Junk midrange decks who curved out into Caryatid, Courser, Blood Baron (a line of play that would stop most aggro decks in their tracks). I've beaten G/R/X decks that curved out similarly. My only match loss playing this at FLGS's so far has been a 1-2 loss to U/W/R control. Games-wise, I think I've won somewhere around 45-50 games and lost around 6. I've lost a game to B/G Devotion, Junk Midrange, Junk Constellation, Esper Control, and two games to American Control. (Edit: See my comment about the recent TCGPlayer 5K for MANY more losses)
I have a few odd card choices here and I'll explain why I made them.
First, I'm playing Spirit of the Labyrinth. As if that wasn't weird in and of itself, it's at the cost of PRECINCT CAPTAIN! Bold, I know. The main reason for this choice was Spirit's body and the fact that it's easier to run Mutavaults and Spirit in the same deck than the mana-greedy Captain. Three power is perfect at the two slot. It punches Caryatid to death, it punches Courser to death with a little help (Spear or Ajani's Presence or Baby Ajani). That's enough said. Beyond that though, its ability is actually relevant against a decent chunk of cards that see standard play: Izzet Charm, Eidolon of Blossoms, Sphinx's Rev, Bident of Thassa, two Underworld Connections, Divination, Azorious Charm, Ephara, Keranos, Read the Bones, and Wild Guess.
Ajani's Presence was an option I just stumbled upon. A main deck four mana counter to Supreme Verdict is a welcome boon to white aggro decks. In tandem with all the 3/1's I play, it can take Courer of Kruphix by surprise. It functions as a counter spell to removal, a combat kill spell, or a means of reaching lethal. This card is worth it.
Outside of those two cards (which are two of the main reasons for the decks success) it's pretty standard fair. You have the good Battalion guys, Mutavaults, and the staple white creatures. A lot of lists skip Banishing Light which I feel is a terrible mistake - playing 6 exile effects main board can be brutal against a lot of decks that don't drop anything worthwhile until turn three anyway. From there if you banish their three and four drops, your win is usually just around the corner if not already secured.
That's all I have to say about it. If you have any more questions, feel free to ask. If you decide to put it together, let me know how it performs for you.
There are several lines of play in this deck. You really have to play every hand as it comes, but I play it very aggressively. I will often push through as much damage as quickly as I can rather than play more creatures. Usually this involves animating Mutavault to trigger Battalion or dropping a Brave the Elements to take a big chunk out of your opponent's life total.
Sideboarding is fairly straightforward.
Versus U/W/X Control:
-3 Banisher Priest
-3 Banishing Light
+3 Frontline Medic
+2 Rootborn Defenses
+1 Godsend
In the early turns don't animate Mutavault unless they are tapped out. Mutavaults will often win you the game against control, so don't throw their lives away if you can help it. The five mana combo of Godsend + Mutavault can be a great way to beat them. Ajani's Presence and Rootborn Defenses both offer counters to Supreme Verdict. The aggressive bodies of your 1 and 2 drops will sometimes end the game before U/W control can get ahold of it.
Versus B/X Devotion:
-3 Banisher Priest
-1 Dryad Militant
+3 Frontline Medic
+1 Banishing Light
This is the snap sideboard choice I make against black. It lets you attack into Desecration Demon and a wall of Pack Rats without losing anything. Pack Rats is the card that can easily beat you here, though. Thankfully, a lot of decks are running less Pack Rats or removing them all together. If this happens, you might have to go to a board stall and set up lethal with Brave the Elements in hand. Use Ajani's Presence and Brave the Elements as counter spells to their removal if they're not going crazy with rat tokens. This is a hard, but definitely winnable matchup. A lot of mono B decks have taken Drown in Sorrow out of their boards which is nice. Golgari Devotion sometimes has Golgari Charm, though, so watch out for that one.
G/R/X Monsters:
-3 Brimaz, King of Oreskos
-3 Dryad Militant
-1 Spear of Heliod
-1 Brave the Elements
+3 Frontline Medic
+3 Celestial Flare
+1 Godsend
+1 Banishing Light
This is what you're meant to beat, daunting as the card advantage in these machines is. You slow down a bit, but you bring in more removal and Godsend is a god-send in this matchup. Celestial Flare can come in as additional answers to Caryatid/Courser walls and of course it's your best answer to Stormbreath Dragon.
G/X/X Enchantress:
-3 Dryad Militant
-1 Spear of Heliod
-1 Brave the Elements
+3 Keening Apparition
+2 Deicide
These decks often feature unexpected sweepers. Doomwake Giant and Golgari Charm can really hurt. Satyr Wayfinder shows up eager to trade. Nyx-Weaver and Courser can also gum up the battlefield. Again, though, this is just a midrange deck that doesn't feature Hexproof so your 6 main deck banishing effects really shine here and your ability to punch through Coursers and other walls makes this a decent matchup.
G/X Hexproof:
-3 Banisher Priest
-2 Imposing Sovereign
-1 Spear of Heliod
+3 Celestial Flare
+2 Deicide
+1 Godsend
Celestial Flare helps a lot if you draw it. Make sure you save it until the last minute or until they get Unflinching Courage on something. Use Deicide on Unflinching Courage as well. Save Banishing Light and Banisher Priest for Voice of Resurgence. I haven't played this matchup more than 2 games (I won 2-0).
RDW/Boros Burn:
-3 Banisher Priest
+3 Frontline Medic
This seems like it might be a tough matchup. A 2/2 First Striker, a creature that does 2 damage whenever you touch a card in your hard, and a spell that kills most of your creatures while dealing 3 to your face. Ouch. On the plus side, exiling is the interaction you want to hit Chandra's Phoenix with. This might be worth devoting two sideboard slots to, but only if you see this deck often. I would consider Blind Obedience as an option.
Mono U Devotion:
-3 Dryad Militant
+1 Banishing Light
+2 Deicide
Militant is kinda crappy against Tidebinder Mage. This matchup is a really good one, though. Save save save save your removal for Master of Waves. I can't stress this enough. Deicide is obviously there for Thassa, but hitting a Bident or if the list is running Hall of Triumph - those are fine choices, too.