Basically they are the same type of large group awareness training (LGAT) program presented over a long weekend in a kind of seminar/intensive format.
See [
www.culteducation.com]
And also [
www.culteducation.com]
They both have the same basic structure, methods etc., but different people derived the profits and ran the companies.
Lifespring was apparently shut down through personal injury lawsuits, though it seems to have reincarnated as "The Legacy Center."
See [
perso.wanadoo.fr]
There are many, many LGAT spin-offs of these groups run by graduates of their programs.
A psychologist Philip Cushman wrote a definitive paper on groups like Lifespring and Landmark, which he called "mass marathon training."
See [
www.culteducation.com]