Lego Serious Play (LSP) is a technic develop by lego for inner brainstorming activities.
It works so well that it has been extend to outside.
I'm a agile Coach and use gamestorming for developing creativity and enhancing standard meeting.
LSP is a very good method and it works very well. There is a specific web site for it : http://www.seriousplay.com and you can download the manual that explain the method.
When considering LSP box, you shouldn't compare the price per piece as it will always be too expensive. The set are useful for their diversity. There is duple, technic, classic, connector, etc... But nothing goes with another as it is not a neat final result witch is intended but a creative result.
So for that the set are very well made and you can modeled almost everything in an enterprise from business process, to making process, or RH, or Sales...
So it's not for AFOL, It's for business and it's really worth the price as you can't made it by yourself with standard sets.
When using the technic, you must have one starter set per person for the beginning and 1 or 2 big sets for 12 persons for the rest of the workshop.