My local Jack in the Box offers them for $4.49, which is 20 cents more than the popular Sourdough Jack.
My particular sourdough slices sported a very nice, slightly buttered, grilled crust. It was a little bit too chewy though and I've never been able to detect any sourness to Jack's sourdough.
The flavors of the sandwich were decent enough, but the steak was weak. Tasting the steak by itself, there's a fair bit of seasoning that gets a lost in the peppers and onions. The steak was also dry and pretty tough. A burger patty would have been more enjoyable and would probably hold up better against the onions and peppers.
Nutritional Info - Jack in the Box Sourdough Cheesesteak Melt
Calories - 456 (from Fat - 222)
Fat - 24g (Saturated Fat - 9g)
Sodium - 1385mg
Carbs - 39g (Sugar - 6g)
Protein - 22g