I've been here a few times and enjoyed the food/drinks but wasn't blown away. I was most recently there on a night that Consol had a concert so the restaurant was PACKED. The waitress was obviously busy (our service was slow) but she managed to keep an eye on our table and did a good job keeping us all satisfied.
The food wasn't anything to call about. The fish tacos were pretty dry and a bit bland, a few others at the table ordered the club and weren't impressed either. However- someone else at the table said the pulled pork sandwich was awesome.
Blue Line is a nice and convenient place to go before a game or concert but it's not really somewhere I would go to 'just because'