I think it would be very unfair to say that one team is better than other, honestly speaking both the teams didn't outshine much in the group stage, they lost against their group toppers and won against the rest of the teams in average games, so no one is the favourite, but just after the toss, the team batting second will become my favourite for sure.
But I can say one thing, if New Zealand wins the game and lifts the world cup, they would prove that they are the best cricket playing nation of this era, almost winning the world cup, winning the WTC, and now lifting the World T20, I am more impressed with the captain because if you see the team isn't very experienced and in all the three tournaments team was quite different from each other and still they have proved themselves as best in all three formats.
Both have qualified for the final which means that both have the potential to win the final. Dew factor is giving unjust benefit to team batting second. Authorities must have taken notice of this factor in advance and should have gone to change timing of the matches. Anyways, we have to play final with that. My team is New Zealand, since they haven't won any WC till date I want to see them lifting the trophy.