If you watched and enjoyed the first season of Love Live! School Idol Project I think you should definitely give the second season a watch. I wouldn't say that this is a flawless anime, but I enjoyed it even more than the first season personally.
*Possible mild spoilers ahead for seasons 1 and 2 of Love Live! Read at your own risk*
There are a few things that are different between this season and the last, mainly just the overall tone and feel of the show I felt shifted a little bit. In the first season there is a constant dilemma, Otonokizaka is going to be shut down so Honoka forms a school idol group in attempt to save it. Every episode pretty much focuses on this, there are challenges, setbacks, small victories, etc, etc, until the school is saved and the idol group is successfully formed.
In this season the first few eipsodes the tone felt very different to me, almost cartoonishly dramatic at times, and at others it felt overly optimistic and inspirational. In fact, after I had finished about the first half of the second season I almost dropped it, I really wasn't feeling super driven by the story. There was the overarching plot of winning Love Live, but it didn't have the same feel as the first season, there wasn't enough at stake, it seemed to me like, of course they are going to win Love Live, how else would it end?
HOWEVER, the second half of the second season was really compelling story-wise. I think I probably cried during the last four or five episodes of the show, it really gave me the bittersweet feeling that I think was intended and I very much felt connected to the characters.
Other than the story, the animation is consistently crisp and pleasing to look at. It's pretty simplistic compared to other anime but it fits the feel of the show. The sound is always good, all the songs that the idols perform are super catchy.
As far as characters go I felt that in the first season Nozomi and Rin were probably the characters that were given the least backstory and development, so I was glad that they both got their moments of development this season. And although I realize that with nine main characters it's difficult to balance the screentime and attention that they are all given, I felt that in this season Umi, Kotori, and Maki were kind of snubbed in that realm. That being said I think I liked all of the girls more than last season, and maybe that's just because there was more time to get attached to them, but I feel like they all developed and became better even as this season progressed.
All of that said, if you liked the first season and never watched or finished this one I would highly recommend it, I found myself enjoying it decently well at the beginning and A LOT at the end. And let it be known that this is about high school girls being school idols, so if that sounds like something you wouldn't like, maybe don't have too high of expectations.