I’m actually surprised to learn that Super Seisyun Brothers is tagged as a josei show on MAL, but after taking a look at the source – a web manga – it kind of starts making sense, at least when it comes to the original art style. I guess my initial ignorance (which did last for over 3 years) was due to the fact that this show aired in Fall 2013, and back then I still didn’t know a lot about anime, and least of all about the stereotypical characteristics of shows aimed at particular demographics. That said, this confusion didn’t really affect my enjoyment of the show, because I genuinely liked most of it anyway.
As the show is about two pairs of siblings, that is to say two older sister-younger brother pairs, Super Seisyun Brothers naturally has lots of themes surrounding sibling love and sibling rivalries, but surprisingly little sexual tension between siblings (which is not uncommon in anime). Depending on what the viewer wants out of the show this can be good or bad, I personally preferred it the non-sexual way.
Instead of that kind of sexuality, though, I feel like the show had a lot of positive attitudes regarding attraction, identity and sexuality in general. Mako likes Chiko, possibly romantically, and Chika and Mao may feel that way about each other as well. Most importantly, though, I can’t remember the show ever categorically shooting down bi- or homosexuality (which is unfortunately somewhat common in anime in my opinion), and I’m very happy about that. The characters are allowed to be who they are or want to be, without any forced bias from the author. I think this is important. It’s possible that I may be grossly misremembering here, but I’ve certainly seen shows that are worse than Super Seisyun Brothers at this.