Both of these shows are about a large group of girls who wish to become popular idols. Most of the girls have never met before so the shows are about them becoming friends and facing idol-related challenges together. If you enjoyed one, you'd probably enjoy the other as well.
the main theme here is idols! so just by that it is clear that there are going to be alot of similarites, but there is with any other idol anime. but with these two animes they are both about a rather large group of girls who start being idols for a greater good e.g. bringing entertainment to the world or saving there school from closing down. which ever one you watch you will see the character development form just normal girls to idols.
Everybody knows it's tough being an idol, especially the girls at 765 Production. Made up of thirteen young ladies, the group constantly attempts to improve its image by taking new promo shots and booking the best gigs possible, whether it's being a concert star or a quirky cooking show guest. Led by the kind-hearted and determined Producer, these talented performers such as twins Mami and Ami, quiet Yukiho, clumsy Haruka and gifted singer Chihaya will do their best to become the best idols around.
If you liked either of these shows, I think you'd be interested in the other. Both of these shows are about a large group of girls who want to be popular idols. Although the setting is very different, they both include group friendship, dance/preformance numbers, and cute music.
AKB0048 is basically inspired by Idolmaster and shares all atributes except the setting which differs greatly between the two. Idolmaster is AKB0048 without the SCI-FI Future fantasy to put it blatantly. Idolmaster takes place in modern time Japan while AKB0048 takes place is a dystopian future.
During a sunny afternoon, Kirarin spots a helpless turtle stuck in a tree. Although Kirarin's mind is always preoccupied with food, she doesn't think twice before saving it; and after the successful rescue, she meets up with the turtle's owner who happens to be a cutie! The guy's name is Seiji and he is actually a famous star! Unfortunately, Seiji's best friend and partner, Hiroto, intrudes on her fantasies claiming that she'd never reach the level of Seiji, and that she should stay away from him. Hiroto's words don't deter her, however; and instead, Kirarin decides to be with Seiji by entering the idol world! However, becoming an idol isn't all fun and games, it's fierce competition, hard work, and filled with rivals!
AKB0048 and Symphogear with have girls singing and fighting. AKB0048 focusses far more on the singing and adds dancing while symphogear focusses mostly on fighting. Both have strong sci-fi elements. AKB0048 more so than Symphogear. If you liked the singing in Symphogear than check AKB0048 out, if you liked the fighting in AKB0048 check Symphogear out, if neither of these apply than don't bother with the other.