Both have the support of the high-ranked party be underappreciated and eventually kicked out or leaving the part of his own volition to then make his own party/harem. In both, the high-ranked party doesn't notice that they're the reason they aren't doing well after the support leaves. In A-Rank Party, I found the magic to be more appealing to watch while in Yuusha Party I liked the characters more, maybe because there was more diversity, I still am not sure. A-Rank party felt like they were actually a party as they worked together to take down the monsters/bosses (similar to Black Summoner maybe). In Yuusha Party, they would make a pact with Rein and then in that party the girls would take the masses or the easier monsters while Rein would take care of the boss from what I can remember.