Now keep in mind my review is for late night stops while getting gas and coming home from Cali/leaving vegas. So, it might be time sensitive, however, this is my honest opinion none the less.
I've gone here several times and each time I go the food is usually a bit over cooked and stale. Not to mention that Jack in the box tends to have greasy food anyways but greasy, over done and stale is not always a pleasant combination ;) I do return because it's often the only place that's open (and it's still better than gas station food at 3 am) on the exit and i'm trying to get back onto I-15 quickly. It's not the most terrible thing out there, but it's far from the best.
Plus almost every time I go they're quite slow for fast food.