The recursive nightmare is real with this deck. Great matchup against basically any meta deck right now. UR control has trouble dealing with this deck. Lost Legacy in the main helps against Marvel matchups for exiling ulamog. Zombies have trouble dealing with the recursion aspect of this deck as its more recursive than their own deck. Even mardu vehicles isn't immune to this decks recursive nature. Weakness seems to lie with matchups against lifegain decks mainly...but most meta decks aren't running this strategy.
Keep in mind all the hate cards in the main (Shamble Back and Lost Legacy) are mainly for use on yourself. Use them to exile Eternal Scourge unless you must use them against your opponent. Lost Legacy can basically get all 4 of your Eternal Scourges exiled in 1 turn, as well as the possibility of exiling a few from your hand for free draws. Epic combo potential. Also, Shamble Back can keep you in the game very well and give you the ability to exile your Scourges while also giving you some board presence with a zombie alongside the 2 life gain.
Scrapheap Scrounger is another Eternal Scourge combo piece. It also Combo's with Syndicate Trafficker to keep giving him counters while you play your exile game.
Noose Constrictor is a very powerful card in this deck. Block pesky flyers and setup for the exile combo with his discard ability or even just use him to setup delirium if it is necessary.
Yahenni, Undying Partisan is basically a tough threat to deal with. Haste is always unexpected by the opponent in a deck like this. His abilities make him a nightmare to deal with, and many times it helps to sacrifice Scrapheap Scrounger to keep the recursion of Eternal Scourge going...getting indestructable in the process on a creature who just keeps growing makes him absolutely bonkers in this deck.
Finally the 3 big guys in the deck. Verdurous Gearhulk is just a big guy to resolve and win the game and Ishkanah is another big threat that flows perfectly in this deck. Delirium is rarely an issue here.
The only complaints I have about this deck is the janky land setup I have at the moment. 4 quagmires seemed like too much...so there is a possibility of getting screwed on green mana occasionally. The Shrine of the Forsaken Gods works great in the late game and even helps fuel the recursion more when Scourge only costs 2 mana to cast. The land base is the only thing I really feel needs some work at the moment.
This deck is also the most swing heavy deck i've ever played. Some matchups you just swing every turn because your creatures just keep returning. This shell is light on removal...because well...who needs removal when you can just block the opponents creatures to death =p.
Feel free to post some suggestions in the comments. Playtest this deck!!!! It is by far one of the most solid decks i've played in the current meta...and I speculate a similar list is going to probably hit competitions eventually, due to the incredible resilience it has against most meta decks!