Master on day 3 of FoX. I don't keep track of winrate but deck does great against all archetypes and most importantly it's fun and interactive.
Edit 1; I got to Masters on day 3 with my FS even mill deck and it's still great. I swapped in only 2x3 new cards from FoX but deck feels smoother than ever.
You have 3 wincons. First is discard, where you only need to mill less than half of opponents deck and drop a Solitude. If the game is tough sometimes I'll drop it much earlier. Leaving 10-15 cards in deck doesn't give them much to play with.
Second is face damage, which mostly works as combo with #3. Dreamsnatcher gets out of hand quickly and you can get him back from the void multiple times. You have plenty of removal to clear the way for him too. Dreamsnatcher loves Corrupt .
Third is Black Iron Manacles. Sometimes I pull 2 of these and just laugh my way to the win while they drop Golems and other card draw. Your Nightfall power cards also play into this because it's suddenly 3 damage.
Oh also, you don't care too much about void hate or silence. It's a bummer but it doesn't kill our deck right away.
Is the basic idea to just make your opponent run out of cards?
Also, for removal bait in first few turns always use Dreamsnatcher because Deathcap is way more valuable.
1) Run the opponent out of cards
2) Damage due to Black Iron Manacles
3) Damage from creatures
Creatures' main priority is to buy time.
Remember the synergy that you between your creatures and spells. Play Dreamsnatchers before mill cards. Play Deathcap before a sigil in your third turn.
But yes, death by solitude is a lot of fun.