So far the only exclusive is Killzone Shadowfall, but that isn't exactly top shelf material, at a whopping 73/100 on Opencritic.
Hopefully Sony has the common sense to keep the heavy hitters like Horizon, Bloodborne, Nioh, and Uncharted 4 off PS Now. Wait until the PS5 gets released and then put all those games on PS Now.
Honestly, I really don't like the idea of paying $10 a month for PSN and $15 a month for PS Now just to play games. But that's probably where this will be headed. Game ownership will be replaced with paying $25 a month for a streaming service. This sort of thing already happened with 3DS Max, and Photoshop. It used to be that you payed around $3,000 for a 3DS Max license that you owned forever. Now they want you paying $240 a month for all eternity. Photoshop used to be $500, with a bunch of other Adobe stuff included. Now that same package is $50 a month, and all your stuff is held hostage on "the cloud".