By slowing down in powerplay overs while batting first, I believe that teams will try to eliminate the impact of losing the toss. It has worked for many teams so far in this tournament. In semi final, Australia's weakness against spin attack got exposed and by considering the New Zealand's spinners' I guess New Zealand got better chances to clinch the cup. Considering batting depth and pace bowling attacks, both of the teams are equally balanced but there could be only difference in spin bowling.
There batting depth was shown in yesterday semi final against Pakistan. Despite 5 wickets down, there number 6 and 7 batsman were strong enough to hit sixes easily. Side batting second has very rear chances of winning, they have chance of winning if they score 200 or more runs otherwise it will be an easy chase. I will place my bet as soon as I see the result of toss, no matter how strong NZ and Australia are side winning toss has more chances of winning.