My saris H3 it's very close to real life when going up hill not drafting anyone etc.... say 10% grade over 5 miles = x mount of time etc... steep grade is mostly power to ratio. flats & down hill is more aero
and rolling resistance.
Down hill is a joke. zwift must give you unlimited gears. How on earth I can pedal at 50+ mph and also do 50rpm + on 15% grade ? That must a rear cassette 5 to 50.
On the flats zwift must assume the most perfect smooth road, zero wind, best bike, game must also assume I am in the best possible aero postion etc.. I am good 2 to 3 mph if not more in zwift vs real life then of course there's so many people you can draft in zwift unlike real life. At home you could be riding on the hoods are even no hands with very bad aero position while on the flats doing 25+ mph.