Both teams are deserving of the champions league trophy this season, both teams have really put in hard work to get to the final. But this a final and one team is definitely going to come out victorious, but if there is one team that's going into the final as under dog that will be PSG. Take it or leave it, many people are favouring inter Milan to win the champions because of the experience that they have got in the competition. They have 3 champions league titles while PSG don't have any. And one thing that makes Inter Milan stand out is that they always make use of whatever chances that comes their way, while PSG miss most of their scoring chances. If PSG wants their chances to increase in the final, they should more clinical up front. PSG missed several scoring chances against Arsenal, while Inter Milan scored most of the chances they got against Barcelona. This is the big difference between this two teams.
You are right. The journey to the Champions League was tough for both teams. In the first round we saw PSG perform very badly. Even the chances of them qualifying for the playoffs were slim. But in the end PSG did it. They beat big teams like Liverpool and Arsenal in the knockout round. This shows that PSG has the potential to win the Champions League.
On the other hand, Inter Milan qualified for the final by beating teams like Barcelona and Bayern Munich. These are two giants on the Champions League platform. Both teams have experienced coaches. Both are in good form at the moment. It is very difficult to predict the outcome of the final. The chances of both winning are 50-50.