First thing that anyone thinks when they see a VN written by Choco Chip is 'nukige!!!'.  That isn't precisely correct.  I've played exactly three games by this guy that impressed me, though that was over four years ago.  Those three games were Prima Stella, Sarasara, and Sakura Iro Quartet.  Randomly, I decided to pick Prima Stella back up, and I relived my ancient experiences with it, gaining new impressions relative to what I've experienced since.

First, my impressions are universally positive about this game.  For those of you who feel negative about that kind of thing, there is sex in the common route (at least one scene for each heroine), but the situations in which they happen aren't too unrealistic as VN situations go, lol.  One of the reasons that Choco Chip's games almost always get put down as nukige is because of his fondness for sexuality in the common route... and that impression isn't entirely wrong.  Most of his VNs really are nukige, through and through.  His VNs are from an era where it wasn't a 'sin' for a nukige to have as solid a plot as your standard VN (as it has pretty much become now, save for rapegames). 

Prima Stella starts with the protagonist, Kousuke, an aspiring swimmer, throwing himself in front of a car to save a girl and little boy without regard for his own safety.  He spends two months in a coma, and when he wakes up, his body is withered and he is barely able to raise his arms.  Well, he manages to finish his basic rehabilitation (enough to live a normal life), but he quickly realizes that getting back in top form is going to be difficult at best, impossible at worst, especially at a school with no indoor pool.  It is at this point that he gets invited to attend school at a famous rich girls' academy, in order to take advantage of the facilities there.  Given the chance, he takes it, and it is there he meets the girl he saved, Shizuka.

This is all given away in the summary, so I'm not really spoiling anything, lol.  Anyway, the common route of the VN focuses on his and the heroines' trials and tribulations, as they all fall in love with him, with legitimate cause (yes, this is the biggest difference between your run of the mill charage, moege, or nukige... there are legitimate reasons for the relationships to form).  Other than that, story-wise there is nothing revolutionary.  The actual heroine paths are as solid as the common route (which is fairly high quality), and the heroines themselves are quite attractive as people. 

One of the things that most charage made in the last few years lack is dealing with heroines deep psychological problems and troubles, and one of the things I liked about this VN was that such troubles do pop up in the story.  Shizuka and Tomoe in particular get a huge dose of this kind of thing, and having the protagonist unwind their twisted hearts is one of the more pleasurable experiences of the VN.

Edit: A few words about the difference in how I felt about this game at the time and how I feel now.  Understand, having played numerous games of the type since my original playthrough,  my viewpoint on slice-of-life VNs has changed immensely.  The first time I played it through, I didn't have the 'eyes' to really see the loving detail that Choco Chip put into this VN... and I didn't have the right mindset to appreciate this type of VN to the fullest (thus my revised vote on vndb). 

One thing that is lacking in today's VNs is the characters' tribulations.  For better or worse, heroines don't have any major issues, protagonists remain the same through the entire VN, and there is no central story to motivate the relationships' growth.   Of course, there are exceptions... but VNs like this one, where the tribulations of the characters go beyond the minor 'drama' that is common in most VNs have gotten rarer and rarer over the last half-decade.