"Best practice" is a fuzzy term and depends on the situation.
I've never been a fan of
relayd and find it hard to recommend in any situation that can be handled without it. For most home or SOHO users, bridging the networks is much more robust, allows "transparent" roaming, and is easier to configure.
When VLANs aren't involved, or they are small in number, and WDS is supported by both devices, that is the simplest approach.
With multiple VLANs, bridging over
greatap or using something like B.A.T.M.A.N. becomes an easier configuration, and doesn't require a dedicated SSID (and associated beacon time) for each VLAN.