Review of The Fruit of Grisaia
I played the visual novel first before seeing this anime. I didn't even know there's anime adaption for it. Here's the deal though. The only thing that prevents me from knowing the original source before the anime adaptation is my expectations for the series. As for Grisaia no Kajitsu, they murdered the hell out of it. Putting the VN aside, the pacing and character development is too fast that you don't understand how and why that character that hated him few episodes ago is already acting all chummy with him. Think of it this way: One episode, every characters are not too friendly with our main protagonist. They areweary about them then the next episode, they're already too close like they have been friends for years.
For VN adaptations with different routes to conquer, they should've just picked they're "main heroine" and continue on that pacing and then add the other routes as an OVA or something (like Clannad).
TL;DR
If you plan to get the VN and haven't watched this series yet, then watch it first before playing the VN BUT if you played the VN and then you plan to watch this anime just to see how well they did, then just don't.