Osawari Island is pretty good, you can target and choose when to activate skills and there's no RNG pathing. I don't know why it's not more popular honestly. It's easy to get SL (the highest rank) girls as well. They're not all created equal but most of them are useful.
Aigis runs horribly on my computer
I did like the TD part but it's not as polished looking as FKG and the grind feels slower too (but that may be because it ran slowly).
I like the simplicity of FKG though. Being able to run in the background is nice too, it doesn't take as much time commitment as the others as long as you're at the computer.