i just finished watching Hibike!Euphonium. overall it is good, but 13 episodes is not enough imo. there are many rooms for characters development, there is also unfinished business (romance) between the main characters, and also the national competition. ending the anime with winning prefectural competition is just...not cool.
i didn't read the novel but the story feels rushed in the anime and i think it deserves second season to make it all clear (and finish the romance, no matter if it will be normal romance or plot twisted and become Yuri )