I started watching Supergirl because it's on Netflix, and I got tired of hate-watching The Walking Dead.
Supergirl is okay. Some of the effects are good, some are bad. Some of the acting is good, some is bad. Melissa Benoist is fine as the titular character. She could stand to learn how to throw a punch though I'm undecided after two episodes if that's the point. If, by the middle of the season, she still doesn't look like she knows what she's doing, it's going to get really hard to finish this.
I know changing a characters' race tends to be a sticking point with people (see Zendaya rumored as Mary Jane which I could go off on*). For me, it's one of those things that I think, "Hmm, that's kind of weird" since I'm used to picturing a character a certain way then I get over it. That said, my issue with Jimmy Olsen isn't that he's a black dude; it's that he's this tall, good-looking dude. I'm getting the impression that Mehcad Brooks was cast because he's an attractive man who can easily be "shipped" with Kara later. There's already a budding love triangle with Winn. Jimmy Olsen is written as this handsome, confident man. How did they get everything about Jimmy Olsen wrong? Olsen is the quintessential dork; he isn't supposed to be cool.
I think that's my main issue with the show. Unless the writers are setting up one hell of a red herring, they changed a beloved fan favorite entirely for a romantic payoff later. Supergirl feels like it's pushing hard for a female audience that probably isn't there, and it reeks of studio executive interference. Since the lead is female, it's as if they felt the show has to be a certain way so it's filled with cliches and tropes that just infuriate me because it's 2016 and everyone should know better. I wasn't a huge fan of Jessica Jones, but I liked that it respected the source material and the writers didn't feel the need to make it "girly" just because it focuses on a female character.
Otherwise, Supergirl is merely okay so far. I'm having difficulty taking Laura Benenti (Alura/Astra) seriously because her Melania Trump impersonation was dead-on, but that's no fault of the show.
*side-note: I didn't want to go on a tangent about Zendaya. Maybe I'll post my thoughts in the Marvel thread