There's basically nothing much to do in Bintan. If I do go to Bintan, it's mainly to slack by the beach at the resort.
The last time I went to Bintan, I stayed at Clubmed. Never left the resort as they had all sorts of activities planned for all ages and food and beverage are available 24/7.
I've also stayed at Banyan Biru villa when I travelled in a big group of 10. And also tried Loola resort, which is an eco friendly resort. It was a great experience!