I eat there every once in a while. The one near me is very well managed. I've been to two other's that were not.
The reason I go to the one near me is that I can have anything on the menu at any time. I, personally detest traditional breakfast foods. I can't have lots of carbs so that leaves eggs for breakfast at most any restaurant that is open in the morning. I really dislike eggs.
At the Black Bear Diner, I can have salad and a sandwich for breakfast. I like that!
I've been to a Black Bear in the Phoenix area for breakfast. Moderate prices, large portions, unlimited coffee refills and a takeout cup. Take your leftovers home and you're set for lunch and maybe even breakfast tomorrow. The leftover sausage patties make a good sandwich. OTOH it's very popular, and I've been back a couple of times when the foyer was full of people and it would have been a long wait to be seated. Time constraints forced me to go elsewhere. They also advertise (or used to) an all-you-can-eat fish fry one night a week. Haven't tried that one yet.
Have eaten at one in CA; it was very good, and the blackberry lemonade, served in Mason jars, was excellent (this was in summer, so it was probably a seasonal or local thing). Portions were generous, food was hot and tasty, service was good. No complaints at all.
I didn't realize it was a franchise chain before this thread. I nearly ate at one while visiting St. George, but wasn't too impressed with it (although it came highly recommended by locals.)
It had a nice ambiance. Don't even recall why I chose not to eat there. Maybe it was the snooty hostess when I asked for a menu to take with me. She was so uppity that I decided no matter how down home it was for the locals, the snobbiness was a real turn-off to me.
I ended up doing Chinese instead. That was pretty good; a local diner. And I left a nice sized tip (always do for good service.)