In short - Maga-Tsuki is a manga every ecchi manga fans should at least try

I personally read most of the manga in one sitting, on the day the last chapter was released. I was hooked up to the story so that I wasn't able to realize that so much time had passed.
Those who complained about this manga were reading it when the manga was being published monthly; but now that the series is completed, you won't feel a lag in the story plot.

Story (8/10)
The way the manga starts is fantastic, as the setting is not a cliche. (a guy who dies if he stays away from a goddess? intersting!) It has classical ecchi scenes you would want to see in an ecchi manga. Some comedy in between also allows some small laughs.
And it has one of much better harem ending.

Art (7/10)
When it comes to ecchi manga, art is crucial to it, and Maga-Tsuki doesn't fall too much apart in that department. It does not have the best art, but the art style itself is great for comedic scenes. Nice and clean

Character (7/10)
Ecchi/Harem mangas usually consist of simple minded characters, but that is alright, as the complexity of character doesn't matter much in an ecchi anime.

Enjoyment (8/10)
This manga has every element that an ecchi/harem fan would like (comedy, classic shots, rom-com, etc.)... What else to ask for?