Let's forget about the performance optimizations that need to come in and some other stuff like sounds, etc.
This game does one simple thing really, really well: COMBAT.
BR genre games should get this fundamental aspect of the genre right and PUB has nailed it. Hey, it's a different style from KOTK (which is more arcadey) and undoubtedly it'll be closer to a sim game like Arma i.e. more deliberate movements and less spontaneous engagements. But for what it is, this game is already really polished and honestly the experience blows KOTK out of the water.
The only thing KOTK I can say has going for it is familiarity/comfort, but the gun combat honestly in PUB already feels AMAZING and satisfying. Every kill is satisfying in this game, because you feel like you had direct input into placing those bullets where you wanted them to go.
Kudos to PU and Bluehole and looks like they are on the right track nailing down the BASIC ELEMENTS of the game. I'm sure with another 6 months to a year of polish this game will be even greater.
I am not sure if the game will reach KOTK popularity because both the skill floor and the skill ceiling are much higher than KOTK. KOTK is much like Mario Kart where the mechanics of the game will undoubtedly bunch people closer together in terms of outcomes.