No, Pretty Little Liars is not funnier than The Middle, because The Middle is the funniest show on television. The Middle is a realistic depiction of what like is life in the Midwest. The situations are real - even down to the ugly blanket on the couch - we have one of those! It's too funny for Pretty Little Liars to be better.
The Middle has an advantage on Pretty Little Liars in terms of being considered 'funnier.' The Middle is actually meant to be amusing, while any humor in Pretty Little Liars is typically unintentional. Pretty Little Liars is meant to be a dramatic, suspenseful television show, whereas The Middle is meant to make you chuckle, at least a little.
In my opinion they aren't very inventive or funny. I don't particularly care for either option. It's a problem with a lot of modern shows, they see the success of other shows and just copy them, it's the reality show issue all over, this time with dramas and comedies. I think that they need to figure some things out and try to develop some new shows that aren't carbon copies of older ones.
I only watched half the first episode of Pretty Little Liars and I was turned off quickly, but from what I can tell it is more of a drama, it may have comedic elements, but the Middle is a straight up comedy. I'm not that crazy about the Middle, but my family likes it and from what I've seen of it there are plenty of funny moments. From what I can tell Pretty Little Liars has little to no funny moments and it's not intended too.
The target audience for Pretty Little Liars is undoubtedly different from the target audience of The middle. Pretty Little Liars is a show about late teenage girls in high school. It is hardly a comedy. The Middle is aimed for all ages and is a family appropriate comedy. I prefer The Middle, as a 21 year old male.