Hi TomP – I think that’s a great question! Thanks for asking! Everyone else, please chime in – I would like to learn, myself.
Ok, here is the deal as I see it: if you plan on staying your entire life in the UN and you would like to be internationally mobile or when you live in DC/NY then the UNFCU is a great choice. They are a credit union with all associated benefits and the challenges of a (smallish) bank.
If you plan to be in Vienna for a while then the UNFCU may not be ideal for you and a local commercial bank (there should be also local credit unions or Genossenschaftsbanken) may be the solution.
If you live in a country with generally no / or a weak banking system, then the UNFCU is great.
I also am aware of a number of UN colleagues that have split salary payments: one portion into the UNFCU account and one into a (e.g. Euro based) local bank.