I have experience of both! Well you have to figure out what is best for you. In my first attempt, I group studied. It was helpful, specially when you were demotivated or frustrated to study but your groupies kept on reading stuff so atleast you could hear information!! But them again, getting overloaded with lot of info is equally detrimental. Lot of time is also wasted sometimes.
Self study requires lot of dedication, isolation and planning. In my second attempt, since I Stuck religiously to my plan and time table, I enjoyed studying by myself. I could follow my intuitions, without a second doubt and had faith in myself. Also, I kept on revising my methods and could actually study faster and efficiently.