Is it worth it to follow(befriend/subscribe to) more than one Pub server? Are all the pub servers synced to each other?
(For this, we can quote verbatim @winmix's answer from the scuttleverse
Many of the pubs sync each other.
note that it's all built on follows. Using an invite to a pub makes you follow the pub (and the people it follows) and that makes it follow you. Following = intention to replicate that persons data where-ever you find it (you find that data via other people via gossip).
following more pubs = finding out about more people getting more pubs to follow you = more always-online nodes that for-sure replicate your messages
Sources
Thanks to @Ds for asking the question and @winmix for the answer!