This feature is available in all editions.
"Effort" is tracked directly against an individual iteration/sprint, project, workitem (story, task, test, etc.) and member. Effort stays with the item when it is moved from one project or sprint, but does not change previous tracked Effort transactions. The total Effort reported for the previous project or sprint remains the same.
Portfolio Items (formerly called Epics) and Backlog Groups (formerly called Feature Groups/Themes) are different in that they simply reflect the Effort for the items are currently assigned to them. Moving an item with Effort from one backlog group to another or from one portfolio item to another will change the rolled up totals on the parent items.