I used paid relays. The reasons are higher quality content. It works alright for spam prevention. Also, I use the nostr.wine filter relay, which is pretty neat. You can connect to it and it will pull notes from your web of contacts (your follows, plus their follows). Additionally, it will rebroadcast your notes to public relays.

It's a pretty nice way to keep your feed quiet (not spammy), but also allow your notes to make it out to the broader public nostr sphere.