Yosuga no Sora

Hm, so does this mean you don't plan to read the VN? I think if you have any plans to read a VN you should always read it before watching the anime adaptation because the adaptation will cut things out or shuffle things around to fit the format. VNs sometimes have ero content that the adaptation can't have, too, so that's something missing.
I see the anime adaptation as a great way to experience it again and see the characters in motion, but at the same time it lessens the the experience of the VN if you read the VN afterwards. Sometimes you get lucky and the anime adaptation adds a bunch of new stuff, which was the case for Utawarerumono 2! It's almost more like a bonus disc or bonus version of the VN! (though it did gloss over things at the same time)

H2O
better than the VN

I don't know if this answers your question well, but I watched Kanon several times before reading the VN. I still liked the VN. There were years of between though.
I've seen Air and Clannad and enjoyed it. I haven't read either of them.
Clannad and Kanon in particular are famously good anime and most people have not read the VNs. The Kanon VN is godtier though and the anime adaption is simply well executed to work as a standalone show.

>>4683
Shuffle! is the only one I've seen that surpasses its source material.
The Galaxy Angel anime is great too but it's so different from the VN that it barely counts.

>>4683
I didn't read a lot of VNs but anime adaptations never appealed to me. The only one I watched until the end was the Planetarian one. It was fine but I still preferred the VN.

There's just too much lost in adaptation. They're better watched after reading the source material.

Amagami and Clannad work well in my opinion for adaptations of route based VNs and they both do it in the exact opposite ways. Amagami uses about 4 episodes for each girl's route, and Clannad mainly uses Nagisa's route as the through line for the entire show with plot points taken from the other routes and adapted into the story. The pros of the Amagami style is allowing each girl their own time to shine with the MC within their own episodes and their own conclusions. With Clannad we get the experience the main ideas and themes wrapped around one romance, but still get the experiences of the other routes without disrupting that.