Mancer is a DEX where your money never leaves your wallet until a trade actually happens, and every trade has a hard price floor baked into the contract, if a fill would be below that floor, the transaction just fails. So whoever executes your order can't screw you on price; the worst they can do is not fill it. That "nobody can give you a bad fill" property is the whole idea, because it lets them eventually hand execution to 5,000 random NFT holders (Chain Mancers) without trusting any of them. Fees turn into ETH and get shared with those NFT holders.