NYC Mesh is a great initiative, and probably the one with the most "modern" setup as it's the newest one. But take into consideration that it might also not be as reliable or work at the same scale as Freifunk or Guifi.
Number of online nodes per network as of today:
- NYC Mesh: 1281 (https://www.nycmesh.net/map)
- Freifunk: 42,524 (https://www.freifunk-karte.de/)
- Guifi: 37,721 (https://guifi.net/en/node/3671/view/nodes)