I've been playing this game for quite a while, and I've held off on reviewing it, because I couldn't quite think of how to balance its strengths and weaknesses. I think it would be a fair assessment to say this game starts off pretty weak and gets better and better as it goes along.
At the beginning, there is a lot of grinding for points as you try to raise the girls' stats, upgrade the hotel, etc. As the game goes along, the hotel management aspects become pretty much moot, and there are not a lot of places where you need to focus on raising any girl's stats.
When the story starts, the MC is pretty much a loser who is in over his head, but over time, becomes more and more confident and competent, and while the female characters at the beginning are often obnoxious and annoying, they have good character development and become much more likable as time goes on. There certain plotlines that go on for way too long (Sarah taking over the island is a really drawn-out and wince-inducing storyline that you would probably be better off rushing through), but her character development afterwards is actually pretty well done for this kind of game, and for video games in general, really.
The game shifts more and more from a grindy sandbox hotel management game with some quests to pretty much a VN in sandbox clothing. The story becomes more and more a slice-of-life manga with BDSM kinks, sex scenes, harem building, and mystical elements thrown in. The graphics are nice, the sex visuals are quite high quality, and the scenarios get better and more creative as the game goes along. The story is also quite long at this point, so there is a lot of content.
If you like story-driven games with likable characters and probably the best character developments I've seen in any game here, I recommend you try this out.