The sooner you join, the less you pay.
A stable release to a small group of innovative managers who voluntarily try the software in an early stage to provide active feedback and directions. Innovators make up a very small percentage of the overall users and enjoy a significant discount.
You wait for the technology to show first results before adopting it. You are ok to pay slightly more, but for a more advanced product.
Modules may contain significant new features but are not the final version yet. These intermediary versions can be used for additional testing and to gather feedback from a wider user base.
You are looking for technology only after it's widely adopted and adapted. Products results have been widely proven.
The Advanced version is the final, polished version that is ready for a public release. It has undergone extensive testing, bug fixing, and refinement and has major advanced features.