Panty & Stocking with Garterbelt

7 words or less 

Angels fight evil for coins using lingerie.

A few more words

As far as magical girls go there are transformations, mascots and episodic giant monsters that explode dramatically when defeated. Pretty much everything you'd expect. Fallen Angels, or decadent angles, whichever you prefer, the main characters have to buy back their access to Heaven by collecting coins which drop as loot from the various ghosts they dispatch. Their weapons of choice: a handgun and a sword for Panty and Stocking respectively.

It doesn't help their cause that Panty is the embodiment of Lust while Stocking is Gluttony personified, the first 2 of the  seven deadly sins as listed on wikipedia. In fact the devils are far more "lawful" and predictable than their counterparts. The priest isn't much better as he's got the stereotypical priestly dark secrets, as well as some others. 

The mascot Chuck, fills the role of Kenny from South Park: comic relief through horrible death, and the only other recurring male character, Brief, has a thing for Panty; she's got a thing for every other male in the world. 

There is a beach episode.

Forgetability 

The art style is easily the most remember-able thing of the series, especially if you've watched The Powerpuff Girls at any moment of your life. Simple shapes and characters, strong outlines and bright colors. While it may look like a low cost cheap solution it's a deliberate artistic choice; this is made clear by the occasional style shift(example below).

The second thing you'll remember is that most characters are named after some kind of undergarment: Panty, Stocking, Brief, Scanty, Kneesocks, Garterbelt. The relevance of undergarments isn't limited to naming sentient beings though, they also double as weapons.

World

The world isn't remarkably interesting. The creativity with western religions is of the same caliber as western creativity with eastern religions: somewhat similar but not really. Heaven treats Earth as a Hell for its angels, but only enforces minimal rules on them. People seem accustomed to giant monsters reigning havoc and they rely entirely on the main characters to save them, though that seems to happen more as a side-effect than anything.

TL;DR: Should I watch it?

Probably. - If not for the humor/story then watch it from a technical execution point of view.