Well, i play both, but they are too different in too many things, if you want to play sneaky, hiding and some things like that, choose PUBG.
With Fortnite, i should say you will have more fun, it is more "simple"(for me) to play, making buildings and play different gamemodes.
Other thing that i have to say is, PUBG requires much more cpu than Fortnite, sometimes you will suffer fps drops too, at the start of the round(without counting all the bugs)
In my opinion, i prefer Fortnite.