I'm surprised nobody has made a thread, yet. Anyway, I'm playing Horizon and loving it. The game looks amazing. Probably the best I've ever seen. Stunning in 4K on PS4 Pro (though Uncharted 4 had a greater impact. I'll have to look at that game, again...).
Gameplay is pretty tight. Details abound. One thing I didn't expect was how much it feels like Rise of the Tomb Raider. The RPG elements haven't really factored in so I feel like it's going to be an RPG like Mass Effect was considered an RPG--more about action and choices.
Great purchase. No regrets so far.
+Simply stunning
+Technically incredible
+MASSIVE feel (so far, anyway)
+Tight, intuitive gameplay
-Takes itself too seriously(?)
-Child Aloy looks kinda creepy
-Some bad voice acting from NPCs (not too bad, though. Just not good.)