>>6
Fate doesn't have that many visual novel entries in it; you've seen pretty much everything there is to see if you complete Stay Night and Hollow Ataraxia, everything else is LNs/anime/video games. Both visual novel entries are quite good, but they're long; finishing all 3 routes in Fate/Stay Night took me around 100 hours, but I played with voices and didn't speedread or anything.

All in all, I recommend it if you have the time. The rest of the entries can be ignored (even Hollow Ataraxia) without losing any real context if you don't feel like going further, but I've become a fan of the franchise in general, I gotta say.