Sub-par EVERYTHING, not worth watching tl;dr - Not worth watching, wish I hadn't
So if you are like me and watched all the Marvel Daredevil, Jessica Jones, Luke Cage and Iron Fist shows before this you'll have noticed the quality went downhill fast by the time Iron Fist came out. I was hoping putting them all together in The Defenders would bring the quality up, but it actually did the opposite. Clearly the producers are coasting on previous success and making 0 effort to make a good show.
The story was unoriginal and poorly written. In fact, everything was poorly written, poorly choreographed, poorly edited. They tried a couple "plot twists" you don't see coming, and you don't, because they make NO SENSE.
Absolutely none of it is believable. Every fight scene starts with a monologue, followed by a team action pose. then badly filmed, badly acted fight scenes, with breaks in the combat to dialog and pose some more. At no point in any episode did I think "yeah, that's a good decision" or "that's how I'd do it", it was just plot hole, bad decision, stupid dialog, plot hole. I only give it 2 stars because I still like Jessica Jones's characters (mostly).