Flash is the best CBM tv show for me, on network tv at least. Nothing beats Daredevil right not but Flash is a close second, it is a bit unfair to compare the two though as DD has much more freedom with the shows direction and how brutal or dark they could go.
Back to Flash, I like it that the show isn't afraid to throw almost any villains and heroes in there and that Flash isn't just running around in a red leather jacket being dubbed the blur.
I truly believe that's where other show fails, you advertise a comic book film, we want to see known characters with superpowers and in costume.
Agents of Shield was pretty bad the first season because it really lacked and superpowers, it also didn't help that it was scheduled with the movie timelines.