did two transits myself upon delayed flights with very tight connections during last 2 months; my impressions:
- there is currently no ground staff to accompany you (even in Biz and with status) or guide you to the shortest way
- coming from Schengen or Americas, you do not have to pass security, but from other destinations you have to pass and have to go all the way back to normal security like all other passengers departing in VIE (there is no transit security in F/G terminal); there is a fast lane however, but that is on the other side than from where you get back to security
- long hauls might wait a couple of minutes for late arriving feeders, but not short haul flights; you are rebooked to the next flight
- I was lucky: I got my luggage twice after 30 minutes transit connections, but I know several other passengers, whose luggage did not make it
- walking distances within the main building with F (Schengen) and G (Non-Schengen) gates are managable even for tight connections. 4 minutes (without running) from one end of the building to the other and less than one minute to change levels