Both are sequels to their original shows and therefore reboots.
Both have enjoyable soundtracks and follow the same idol pattern as this show "problem, solution, song, epilogue"
Both main characters are heavily into dreams with Yume meaning dream and her entire character being that she is following her idol dream.
These 2 anime are both idol anime.
They have fantastic music and performances. In both anime, the characters are trying to become top idol or divine idol. The 2 anime almost always have a performance per episode. They both have machines that can change the idol's clothes.
Although there are a few differences such as Aikatsu Stars!'s setting is usually in a school while Pripara's setting is half school and half in Pripara.
LOVE LIVE has been one of my favorite anime since i joined the otaku world. it's fun and entertaining especially their performance and songs. you can also find similarities with this anime but aikatsu stars is a bit different with LOVE LIVE since the idols work individually in aikatsu.