There is no difference between these two versions of Moxie in terms of usability and functionality. The difference is the installation Wizard.
Moxie 6.09R2 does not support the use of a Data Server Proxy. This option was removed from the second installer package (6.09.4470.4) to avoid confusion. The first version (6.09.4428.2) still has the option for Proxy in the installation Wizard, although Proxy is not supported in this version either. Both of these versions are referred to as Moxie 6.09R2
Clients who need Moxie Data Proxy are advised to wait until the announcement of 6.09R3 before attempting to upgrade their systems.