Just finished this anime after a long break from animes.
Plot: Its basically a mecha anime set in a world 107 years after the destruction of the Moon due to unknown reasons.
Remnants of the destruction of the Moon aka "Drops" are usually destroyed by missiles; however, since Japan cannot have a missile system under the Three Non-Nuclear Principles, they are assigned iDOLs(the mechas) in order to destroy the drops. iDOL pilots have to be girls and they have to chosen by the iDOL itself. These girls are called iDOLmasters.
The show centers around Haruka Amami; (and her friends) initially underconfident with herself, she passes an audition to be a singing idol and is sent to Tokyo to start a career in the entertainment. She doesn't know that the agency that recruited her is actually a front for a big task force which uses iDOLs to save the Earth from falling fragmented pieces of the moon.
However it would seem these Drops would be least of the problems faced.
Review: The overall character development was quite impressive, with a thorough history of most of the girls being given. It does however have alot of similarities with Mai-Hime (which may or may not be a plus for you :))as the same staff worked on both but this feels much better than Mai-Hime.
Overall I would give it a 8.5 and would recommend this anime to those who are looking for something to watch.
Here are some pictures of the characters in interesting positions.