I haven't seen many people discussing Game Share presumably because most games don't support it, but Split Fiction allows you to play with a Switch 1 which is a really cool feature. Unfortunately, it was pretty much unplayable.
Game Share works by streaming, which means the quality is quite variable but not too bad. Latency was minimal in terms of the video and inputs. Unfortunately, despite fast internet and having both consoles next to each other and the router, we frequently experienced freezing which made the game almost unplayable. I'm not actually sure if internet speed matters at all since it's local.
I'm not able to test with another Switch 2 or over the internet, so I'm not sure if the experience is improved over Switch 2. I've seen mixed feedback on here about Game Share with some positive and negative experiences, but this Nintendolife review seems to have had the same issue I did.
As I said the experience otherwise was fine, it would be great for a turn-based game, but for a game like Split Fiction the frequent freezing ruined it. Split Fiction is great otherwise!
by Tim-Sanchez