A great combination of easy puzzles and only moderate grind, beautiful original art, animated scenes that can be, within limits, customized, sexy characters, an interesting story that involves character development, plenty of choices on how to train your slaves.
(for example when you have more than one slave you can decide which chicks are more submissive or more dominant in a scene)
Overall I think the combination of those factors make it far superior to games that have a good story but no animations (or text only, or only use random images from the net), games that involve a lot of tedious game playing (and usually have little art and no animations for H scenes), games that use theoretically superior but practically poorly made 3D art, or tedious Japanese products in which all the characters are pretty much all the same and have no subtlety in their writing (as soon as the H begins, the chicks turn into nymphos).
(for example when you have more than one slave you can decide which chicks are more submissive or more dominant in a scene)
Overall I think the combination of those factors make it far superior to games that have a good story but no animations (or text only, or only use random images from the net), games that involve a lot of tedious game playing (and usually have little art and no animations for H scenes), games that use theoretically superior but practically poorly made 3D art, or tedious Japanese products in which all the characters are pretty much all the same and have no subtlety in their writing (as soon as the H begins, the chicks turn into nymphos).