I'll reference the first season but without spoilers. If you are thinking about starting the first season, do it only if you plan to get any deeper into the series later. The anime is a good starting point to know a bit about the characters and their music. If you already watched and liked it, then you will like S2 too. The format is the same, and seeing how our boys changed now that they are 4 years older is nice. :) About the story and characters: it's episodic, there's barely any plot. But it does the job well, which is showing each idol's personality and their relationshipswith the other idols. They mostly go by pairings, and their dynamics are really nice. (I love Arata and Aoi so much.)

About the animation: overall it's the typical of low budget. But hey, the characters look pretty, that compensates the lack of movement. Just look at the adults in Hajime's episode. And the 3D MVs are really good.

Sound: I can't say much because I don't really pay attention to the background soundtracks, but the ending songs are really good. Then the VAs, expect a really experienced cast (since Tsukiuta started in 2013), they are all seriously good singers and voice actors.

Conclusion: mediocre anime but worth watching if you want to get into Tsukiuta. It's good, I promise. There's no way you won't like any of their songs because each character has a different composer and a completely different style (most of them are popular Vocaloid composers, in case this grabs your attention).

As my first review, I hope this was any helpful. The series of Tsukino Talent need more love. :)