I don't understand the hype, but it's not bad.
I got the double double with peppers, and it was okay-to-good, but I still felt that gross fast food feeling afterward. I guess I was expecting it to be super fresh? I went on a Friday night, and the place was so full that we shared a table with some other people which wasn't a big deal. The service was great, and one of the staff even offered to bring our food over to our table. The fries tasted okay.
If I had to pick between In-N-Out and Whataburger, I would pick Whataburger any day, but maybe that's the Texan in me coming out.