I've been a big fan of Netflix's Marvel line-up.
Daredevil was excellent. Jessica Jones was even better in a lot of ways. Iron Fist (hopefully) will be good...
Luke Cage, however, has been a bust... Part of that is (probably) due to source material, but I can't say for certain. All I've seen from Luke Cage as far as comics go was one or two guest spots in a Daredevil comic, and he didn't exactly impress. The outfit is goofy as can be, his catchphrase "Sweet Christmas" is groan-inducing, and there's just not much particularly interesting about him - super strong, invulnerable - kind of a black, flightless Superman.
The show improves on some of these things... Thankfully, the costume is done away with after a brief origin scene. He does say "Sweet Christmas," as well as "Sweet Sister," and probably a couple other "sweet" things... but there's really only so much that can be done.
Cage's "super power" is that he is unbreakable. Nothing can hurt him. Bullets, fists, blades - nothing. So most "fight" scenes are him walking through a storm of bullets and/or knocking people away with a flick of his wrist. Not very interesting. He does come up against some skeletons from his closet that exploit his weaknesses, but there's never any tension that Luke could actually be seriously harmed. Boring. And he doesn't exactly have a winning personality, either. He's big, quiet, will stand up for himself and others... And that's basically it.
The creative forces behind the show Luke Cage did the best they could - trying to ground Cage in reality, make him less ridiculous, more believable, more relatable - but those very forces aren't exactly potent either. I commend the show creators for tying into politics and current events (hoodies play a very big part in the show, as well as police-minority tensions), but this is a boring, prosaic show.
The best that can be said about Luke Cage, even at its best, is that it's competent. The action scenes are mundane, the direction pedestrian, the cinematography flat and uninspired... The music is excellent throughout, but that (honestly) is the best thing about the show. Which is a shame. Netflix and Marvel had made quite a formidable team - delivering numerous seasons of high-quality, cinematic television that reinvigorated a flagging brand after diminishing returns from multiple box office efforts, as well as a steep drop in quality.
Here's hoping Luke Cage was a fluke, and that Iron Fist will get them back on top.