LogFAQs > #961266180

This is tricky. I'll go with an 8.5/10, with the caveat that I'd rate the different routes of the VN somewhat differently.

The Fate route is something like a 7 or 8; the UBW route is something like a 6 or a 7; and Heaven's Feel is something like a 9 or a 10.

Overall rating is a bit higher than the sum of its parts because I like how the 3 routes taken together provide something of a complete picture of Shirou and his ideals and how they can change. It's really neat how I can view Fate Shirou, UBW Shirou, and HF Shirou as meaningfully different characters, which isn't something I can recall too often from other VN's I've read. You get this a bit from the other characters also but you unsurprisingly get the most insight into Shirou since he's the main character.

Also the rating probably should have said as much but I do count Heaven's Feel among my all-time favorite stories.