The next big platform to go down will be Hashflare. They reneged on the lifetime contracts, upped the minimum withdraw to 0.05 BTC so a 3 TH/s miner won't get paid for 6 months, and they don't have the infrastructure. Hashing24 still honors the lifetime contract and they have all that Bitfury infrastructure. They are sold out, so you can't really promote them, but they are sold out for a reason. They just started auctioning contracts, have not tried it.