Surely the guide should be comparative travel times for real journeys.
For example, Paris to Nice. How long does it take, on average (not fastest achievable by racing) to get from Notre-Dame to Place Masséna by public transport (1) by TGV, (2) by air, including travel time to station/airport, check-in, security, sitting around waiting to board, boarding, gate-to-gate time of train or plane, getting out of station/airport, travel time to destination? I don't know, but I'd bet on the TGV winning.