Note that both the versions are licensed per developer. Here are the differences between the 2 versions:
The Regular Edition provides you the following:
- Includes 1 Year of Subscription.
- Unlimited Support (2 day response time) while Subscribed.
- Access to all Official releases while Subscribed.
The Enterprise (or Source) Edition provides you the following:
- Includes 1 Year of Subscription.
- Full unminified, debuggable Source for our Gantt Widgets.
- Priority, Unlimited Support (1 day response time) while Subscribed.
- Access to all Official and unofficial releases while Subscribed.