This is something I struggled with about a week ago, while drafting my WIP. I'm about 50k words deep, and I decided to try third person as I kept writing. After about 2k words, I decided to scrap that idea, and stick with first person. Here's why: My character is not a bad guy, but not entirely good either. He's very immature and tends to learn things the hard way. After seeing how my story reads in third person, I decided that my readers will have more fun with a first person POV. But... another book I will write after my current WIP is totally different. It's fantasy/horror, and I think third person will work much better for that one. Or maybe not. I haven't even developed a strong main character for that one yet. I'll probably know more when I hit 50k words.