If you liked the Someday's Dreamers anime, the Anime-Planet community thinks you'd like:
The cheery Kobato Hanato is on a mission to heal people’s damaged hearts and gather the resulting “konpeito”; she must collect one hundred of these candy-shaped trophies in order for her deepest wish to be granted: to go to a certain place. Along the way, she’s accompanied by an ever-disgruntled, talking stuffed animal of a guardian named Ioryogi who scores her efforts, attempts to keep her on-track, and reminds her of the rules governing her task: she only has one year to fulfill her goal and she must not, under any circumstance, fall in love with someone whose heart she heals.
Both the protagonists are young magical student girls trying to learn how to use magic for good. They are both put through various test and trials that helps them learn what it means to help others. They both learn how to help others achieve happiness.
Deep in the mountains lies a library with the same name as one of its caretakers, Kokoro. With her sisters Inna and Aruto, she strives to uphold the best characteristic of a librarian -- to help users with all her heart. Join young Kokoro as she starts the journey to become a full-fledged librarian, while learning about life, and being the best she can be.
Guided by a star only they can see, a group of maidens known as HiMEs have begun to gather at Fuuka Academy. These young women have been endowed with dangerous supernatural powers that they can use to their heart's content, but there's a price: to wield them, they must put their most important thing on the line. Now, in the midst of school work and friendships, they find themselves caught in the midst of strange conspiracies seemingly related to the terrifying monsters that attack them. Is the power of the HiMEs strong enough to save themselves and the ones they love?
Miu is a young, talented pianist with a passion for playing music. Under the guidance of Shirakawa, her teacher, she decides to enter a recital, where she will play an emotional, self-written piece.Piano is a quiet story about first loves, friendship, and the challenges one must overcome to succeed.
Someday's Dreamers and Piano both have a very similar, beautiful animation style.. but more importantly, both are charming, quiet, slow tales of the everyday life of a girl who is trying to succeed, even when it seems impossible. If you've seen one, I really don't think it's possible that you'd dislike the other.
When Asumi was just a baby, a space shuttle accident changed her life, and the lives of the townspeople of Yuigahama, forever. As a young woman, the spirited Asumi has only one desire: to someday travel to the stars in a rocket, with her father and ghostly friend Lion-san along for the ride. With heartache, happiness, and plenty of determination, Asumi and dozens of talented teenagers now face the greatest challenge of their lives: the test to enter a prestigious space academy, so that they may one day reach out and touch the stars...
Completely different plots, but I just got a similar feel from watching both of these. Both are heavy on character development, though Twin Spica does have a bit more plot. In general, each are about a girl trying to succeed in her chosen field, against all odds. You'll get a light hearted and wonderful feeling after watching each episode of both of these shows. I definitely think if you like one, you would like the other.