You either ask if you should read a specific manga (or see a anime) or tell the post above if he/she should or not. You dont have to ad reason, but it would be great if you did.
I will start: Should I read Bleach?
It depends on personal preference. I would say Bleach was good in the beginning and has cool concepts but the author tends to mess some things up(not like author authors don't but you get the point). I say you should read the first arc and see if you like it. If you do, continue it. If, not, you know what to do.
EDIT: Should I read Seven Deadly sins? I've heard some stuff about it but I don't know whether to read it or not.
Read Blue Exorcist. The anime is cut short and diverges around episode 17 or 18 into an anime exclusive ending. Can't remember what episode number. Plus, the characters are underdeveloped in a short manner. You won't get much satisfaction from watching the anime.
Should I read or watch Negima?
If you want uncensored violence and blood, read the manga. The anime ends in an anime exclusive ending. As Taichokage put it, it won't be able to start up the Billion Bird Arc. The anime needs a reboot.
For anime, it's not bad. If you read the manga first, you will notice the slight drop in the aesthetics and art style in the anime.
Check out the TORIKO Roundtable. WayBig did a good job analyzing the flaws, but watch out for spoilers.
Should I read or watch Love Hina?
@SMXLR8: Attack on Titan is great. I really enjoyed and it's one of my top 30 favorites, albeit low on that list. People like to say how Eren is an amazing protagonist, but honestly he is pretty average imo. He is not bad, but he is no Goku or Yusuke.
Should I watch Mondaiji?