From personal experience, especially as I'm studying for the ATPL at the moment, I find a classroom environment benefitial in the sense it keeps you moving forward at a good pace and it helps with being in a "teaching environment". On the other hand, I need time to digest what I read and also a quiet room, this is not something that a classroom can provide. I've spent ages learning Bristol's material and I'm sure that the time I've spent will benefit me when it comes to the brush-up.
As the original poster has commented about flying with another pilot, I agree, this is a very usual way of working. Spreading the work load, enjoying the flight more, feeling more relaxed and potentially learn more from each other!
But flying solo builds one's confidence in his/her ability.