I mean I tried In-N-Out, but it was just... Fine? Maybe it was over-hyped before I tried it, but I wasn't blown away. It didn't do anything wrong, but it didn't do anything for me.
My comments were steered more towards the burgers, but I will say none of the places I mentioned impressed me with the fries (esp Whataburger).
I feel like in n out fries by default are way too under-cooked. They're basically floppy little potato tubes. You can order them light well and they fry them for just a bit longer so they don't suck. You can also get them well done, but then they're basically just potato chip sticks.