YEGHRO paid relay actually uses a private #WoT relay that runs on my follow list which I keep fine tuned using YEGHRO unFollow tool to keep the follow list the WoT is based on clean as I possibly can.
And on top of all that the content is filtered to ensure more quality content gets through.
It does a good job of capturing a good chunk of the #nostr network allowing users the option to limit their public relays significantly if they'd like to avoid spam.