At first I would have picked Finn over Bellamy any day but as season one went on, Bellamy seem to change in my eyes. I originally saw him as some grown up brat who was power hungry but I was wrong. His character was more complex then that. I now see him as the leader who has done things that he's not proud of but he does it because he thinks he's right. Finn was just a boring generic good guy until he snapped. I will admit it was a good end to his character but he was too boring in the beginning for me to put him over Bellamy. Bellamy Blake has always had me invested in the show and I also am excited for the next season.
Okay so, I realize that Bellamy was not the best guy at the beginning but over time he really opened up and you could see his love for his sister and his feelings growing towards Clarke. He knew that the 100 needed a leader, and he thought he knew what was best, turns out he didn't but then he did so whatever. I am so pumped for the next season.