Studying alone, in pairs or in groups?

I've found out that I study the best as a lone wolf since I've never experienced any improvements in groups. I've had more drawbacks than benefits with the groups.

In pairs, I've found that it only works if the other person is at almost the same level of understanding the subject as I am, so we can fill the little details we might have missed between each other.

What works best for you in your studies - studying alone, in pairs or in groups?