I like I said before it was really hard to choose! I love both!and it's really hard for me to compare them as well..but anyway of the two Shugo Chara wins this for me.
This is a rather odd comparison. Hetalia or Shugo Chara? They are both very different animes and each has their good and bad things. It's obvious that Hetalia is liked more though. Hetalia if loved a ton and people rave over it where Shugo Chara is more of a normal liked anime. So comparing them seems a bit unfair. I'm not trying to criticize the question I am just stating that Hetalia is MUCH more liked then Shugo Chara by a long shot. Sorry.
I pick Rebellion~ And refuse to choice ;)