It has to be said: PUBG - considering the sheer size and scope of its reach, ambitions and money taken so far - really should run flawlessly. Its 1.0 update on PC saw the biggest boost to general playability so far, implementing an ultra-cool Theatre/replay mode and touching up performance across the board - though it's far from perfect.
Symptomatic of so many users' individual setups being customisable and different per person, there are endless guides geared towards how to "spec your rig" into getting PUBG into the best working condition. Even then, users report on a daily basis as to frame rate drops and crashes, as one fix for a certain group can be disastrous for the rest.
That's all par for the course on PC, but even over on Xbox One - where hardware specs are locked, and only two variations exist if you extend to an Xbox One X's capabilities - PUBG struggles to maintain even 30fps, especially when in a vehicle or engaging multiple players.
Over to Fortnite, and clearly Epic have targeted performance as a major boon to playability. Noting how millions of users were having trouble getting PUBG off the ground, Fortnite loads far faster, has had demonstrably more work put into movement animations, and holds steady at 60fps even during the most frenetic encounters.
There's no contest here, though I hope some day there will be.