At first I thought this was so typical and boring that it was going to put me to sleep. I almost instantly hated it, like a crappier version of FLCL. This started to change by the second issue, and so on.
Still I think there's like an 80%(at best) chance of someone's best friend, at that age, that you walk to and from school, being a girl. Why the heck is that so common, I'm seriously protesting that(unrelated to this manga though).
The humour is not outrageous but quite noticeable without being totally ridiculous. Meaning its more down to earth, based on dialogue, than gags.
It also pretty quickly starts to differentiate itself with its premise. That's relative though, there's only a few issues, in terms of the few issues out, the humour seeping in has been slow as oppose to be there, as it is, since day one. The way the premise is slowly doled out might hurt it in the first chapter but it's done that way to really build the atmosphere.
What started out so typical, ends up being quite different. The action is more subdued, the reality is exaggerated, but not to the extent of a fight manga or some such.