The more nodes you have connected (i.e. the closer to full mesh rather than hub/spoke) the more efficient the syncing will be and nodes will get in sync faster. However each node (currently, this is due to be changed in v0.9) keeps the index of other connected nodes in RAM, so the more connected nodes the higher memory utilization. I expect a good trade off to be around ten peers; at least I haven’t tested for more. Syncthing will work fine even in a 100 node daisy chain, changes will just take a little longer to propagate from node 1 to mode 100.