This is a great formation to play if you have the right type of players. It can be a fantastic system to pass the ball in, as it lends to forming triangles all over the pitch.
A number of professional teams have adopted this way of playing over the years, with Glenn Hoddle being a great advocate of this formation in his time as Swindon and Chelsea manager.
The use of a sweeper and wing backs allows the team to really spread out and make the pitch big when in possession of the ball. This makes it very difficult to play against if you have players who are comfortable on the ball and can pass it well.
The only real weakness of this set-up is that you can get exposed in advanced wide areas, behind your wing backs, especially when your wing backs start to tire as they have a huge workload in this system.