This game as massive technical issues on PS4. It crashes every 5 minutes. I was able to track down the reason to the Ubisoft Connect service that was rushed to market and is utterly broken. Besides running the game on PS4, I also own a license on PC and like to cross-play on both platforms. That's where Ubisoft Connect steps in and causes all the crashes.
Other than that, the game is what you expect. An interesting pseud-historical context, fun fights and great exploration. Graphics is alright, but suffers from outdated character models. Gameplay is also somewhat repetitive, so don't buy if you don't like that.
Whoever is interested in the series better waits for Ubisoft to fix the bugs and pick it up when it goes on sale.