Home page is papermc.io

Their tagline - Paper is the next generation of Minecraft server, compatible with Spigot plugins and offering uncompromising performance.

I used Paper few times. I like Spigot more, but when I used Paper all the Spigot plugins worked just like they were on Spigot. I didn't try but I think there is no problem using ScriptCraft on Paper.

I'm running it on a Paper server now (1.16.5). Most of the things I have tried seems to be working, apart from the drone. I haven't done an extensive test though as I have mainly used it to play with the bukkit/spigot/paper apis.

Yes, I've used it too, and haven't noticed any differences.

Since Paper is downstream from Spigot, I always feel a timing issue: When Minecraft v1.17 is available, for example, we need to wait for the Spigot team to catch up. That can take weeks or months - it's FOSS and just takes as long as it takes. Then the Paper folks get it and do their magic. There is yet another period required to wait for confirmation of stability. Then we need to wait for SCJS to incorporate the new features. Sure, some of this happens in parallel rather than in series - there are no absolutes. But we wait a LONG time for each new version of Minecraft. How long do we then want to wait for Spigot, and then Paper, and then ScriptCraftJS, so that we can actually just play and enjoy the game? Meh, I don't have that much patience. YMMV