As you can see, I'm obviously a fan, and for me, it actually depends on your taste and how open-minded you are, because Hetalia is a parody of the World Wars.
I'm not saying that the haters are wrong and the lovers are right and/ or vice versa.
I understand why some people dislike the series because they might have had relatives who died in the wars and seeing that Hetalia made it seem like a joke angers them. Others may have other views in their countries and hate Hetalia because Himaruya, for them, portrays their country wrongly, like Korea. Korea banned Hetalia because they found it offending and all. Some hate it because they say it's yaoi and all. Well, personally, Himaruya gave a few hints of yaoi in the manga but he didn't include any kind of /actual yaoi/ that shows countries doing "it".
The suggestion I have for you is you should try it only if you are really open-minded with stereotypes and such, but overall, it's funny, interesting, and you learn some real history from it, too.