At the end of the day they all basically do the same thing. Nostr.wine is good like Derek said, they offer some sort of filtering that slows to some control on how the relay behaves for you but unless you’re a techie it’s kinda confusing to deal with (at-least the last time I checked). The providers may have something or another that makes them stand out. For example YEGHRO relay (my relay) is setup in a way that tries to get as much Nostr content from the network as possible while filtering out gross undesirable content and it only stores data from the last 48 hours unless you’re a member then it stores your data indefinitely or until you ask me to wipe you and your data from the relay.

I think ultimately it comes down to the people running the relays. If you like them and want to support them then sign up to their relay service.