What I liked the most are 2 aspects of the game:Depend what you like in it.
From the same company you got the older AA 1 / 2 (Artificial Academy 1 / 2) that some peoples prefer over Koikatsu.
Some diffenrence in the gameplay and graphism, but there tons of mods too if you can found link still alive (don't know about mods for position).
The only other that come to mind is KISS' "custom maid" serie. Sadly the company got so many dlc for extra custom that the official english version are only having a small portion of them, and the unoficial patches often are using auto translation for part of the content.
1) Character creation - It's simple too good, you can go crazy, especially with mods/plugins. Besides, it's very satisfying when you start to learn how to use the character creation and improve your designs.
2) The sandbox / datingsim - You don't have so many options, but it fits and gives an actual gameplay to the game.
I'll go check KISS "custom maid" series, thanks for the recommendation!