Just how bad is the One camera?

I previously has an S4 and I thought it had a terrible camera compared to my old iPhone 4s. Pictures would come out blurry half the time and I'd get into a habit of taking multiple shots just in case.

I'm now looking for a new phone and I love everything about the One, except the camera. 4mp!? So, how bad is it really in everyday use. I'm no photographer but I do take lots if pics for Facebook and Instagram and family sharing.

Should I plunge for the one? Or go for an iPhone again?