I'm currently three weeks into a Physics class that's modeled on this concept. Let me tell you what it's like.
In theory: Students review the lecture material on their own time. In class, the instructor presents some Physics problems on the topic. The students work through them together in teams and learn from each other, and the instructor reviews each team's work to help them get past sticking points.
In practice: I review the lecture material on my own time. My classmates do not. They show up largely unprepared, and when presented with a basic problem, simply stare at it until someone else explains the entire problem to them. Typically, that means that I end up teaching my classmates Physics, and then showing them how I solved each of the problems. I need to do that, because a significant part of my grade is based on the performance of my team - i.e., the average of individual quiz scores of the members of my team.
The instructor routinely harangues students to come to class prepared, and is assigning increasing amounts of busywork to be performed outside of class to ensure that work is being done.
So for me - a very reliable self-starter and independent studier - this class model means that in addition to learning all of the material on my own, I also have to (1) spend several hours in class teaching the material to my classmates, (2) have my grade dragged down by my team members' poor performance, and (3) have to complete additional work outside of class to prove that I'm keeping up. In other words, of the 10+ hours a week that this class is requiring, LESS THAN HALF is spent learning the material and honing skills; the rest (including the 4+ hours of class time) is simply wasted, thanks to this poorly implemented learning model.