Yes, we use both, and there is no significant difference in meaning between 'What do you think of laptops?' and 'What do you think about laptops?'

Can't answer as to laptops specifically. However, I asked a friend just the other day what she thought about her new smart phone. If I had been asking about smart phones in general, I think I would have asked what she thought of smart phones. The "of" in that case indicating more of a category question as opposed to a specific question regarding her smart phone where I used "about". Hadn't even realized I was making that kind of a differentiation until I saw your question.