Leaving Calvinism: Leighton Flowers
Leighton Flowers is a former 5-point Calvinist who now writes extensively against Calvinism at Soteriology 101. His writing is very concise, polite, and easy-to-understand. I've visited his site a lot since experiencing Calvinism in our church, and it's one of the top ones I recommend. My husband and 17-year-old son listen to him all the time. Here is his YouTube channel and his Facebook page.
Here is his story of leaving Calvinism: The 5 Points That Led Me To Leave Calvinism