both have a centaur girl as a character though Monster Musume no Iru Nichijou is super ecchi and has other monster girls vying for the main heroine spot. Either way, if you love having fun with monster girls, then have fun with both of these
Taking place in a modern setting, both series consists of a character casts made up of non-human characters. In essence, the story tells about their lives including what they do every day and how they function as who they are. There is a good amount of comedy for both series and character relationships. Monster Musume is more known for its immense amount of fan service while Centaur no Nayami appeals to slice of life.
Both series has a casual way of storytelling with slice of life dynamics. Nonetheless, they have a small yet colorful cast of characters with appealing personalities. Every chapter offers something new to the readers with everyday life events. If you find a slice of life appealing with charming attributes, then definitely consider both of these titles.
Both of them are very relaxing without much going on. kemonomimis are a plus. The Nukos in Nukoduke are very adorable like most of the younger characters in Centaur no Nayami. For me the main purpose of reading these are to fill up my Awww meter so this is another one to check out while waiting for updates..
Both focus on monster girls and have a sort of scientific feel to them. One has only a few demihumans, and the other a whole world. Both explore their daily lives and problems that result from their unique traits.
Fantasy-oriented SOL comedies featuring mythological creatures living in the real world (in the case of Kobayashi-san, dragons). Some shoujo ai undertones are present throughout as well as fanservice.
Although one is different and probably more drama-focused than the other, they all make for a relaxing read.
Both manga are seinen supernatural slice-of-life manga following a monster girl female main character going about their daily lives interacting with others. If you enjoyed one, you will most likely enjoy the other.
Both series shows daily lives with occasional bizarre incident involving alien/ghost/dimension travel etc. The concept of "daily lives goes by even when bizarre thing happened" shown by combining normal daily lives & supernatural phenomenon. The difference is that Soremachi got normal human neighborhood as a setting while Centaur take a setting in modern-ish fantasy world.
With a slice of life mood, both series adapts a story with a lighthearted atmosphere with a cast of peculiar characters. It's noticeable that both series has supernatural themes with a lot of parody and gags. Centaur no Nayami occasionally adapts more of a serious tone with emotional appeal while Shinryaku has more comedy.