Just to remind everyone that anecdote != anecdata, I've got a 3xl with one of the fabric cases. No scratches yet, and it's even been dropped a few times with nothing to show for it. In short, I think the screen is great.
It's certainly a far cry from my previous phone (Galaxy S6), which was dented and scratched within a month (maybe two? it's been a few years). I had to give in and buy a protective case for the S6, but I don't see that happening for the 3xl.
Chances are it's very dependent on what you do with your phone, as always. Mine sits on a desk/table or plugged into my car most of the time, and only ends up in my pocket (without keys!) when I'm walking somewhere.