First of all: I watched season 1 and 2 as one whole Season. And that is the ground this recommendation is based on.
If you watched and liked season 1, you need to watch this too. I wouldn't say this season is better or worse, it's just different. The first season was a bit more introduction and prequel as fighting and pushing the real story forward like this season.
I loved the first season and i loved this season. This one is sometimes a bit more complex and it does an amazing job playing in the "grey area" where you really can't decide for wich "team" you should root for.
But beware: This show NEEDS a 3 season. There are almost all questions left open and it ends with a huge cliffhanger. So if there is no 3 Season, don't start watching the show (that's btw the only reason for "recommended" and not "must watch"). Unless you want spending your time with a great Anime and have no problem with unresolved questions and an unfinished anime. :)