I dunno to me its pretty good.. if mediocre is median-yeah probably. The price is right, for me consistent, and there are some items I like. When I walk in the door I know what I'm getting. It is steps up from most fast food outlets and not that much more $.
Tastes in food are so varied it is hard to get complete consensus on a restaurant. I've been in some very well regarded restaurants with beautiful food prep, quality ingredients, nice setting, etc. where I just didn't enjoy the flavors. We are very fortunate to have so much good food to choose from.