If Add2Exchange was working and now it's not, post here.
The first replication takes the longest. Then we only sync Deltas or changes. Dereplication takes less time.
Adding users of course adds to the time it takes to replicate.
For Add2Outlook, it is best to add all the users at once.
For Add2Exchange , it doesn't matter. You can add and remove at will for nominal changes.
To be able to tell how long it will take after a sync, we would look at utility in the console for sync interval and make note of the time.
We don't recommend any time less than 10 minutes, because it will always be syncing and users may not have enough time to open it and save changes.
From there we would then go into the Add2Exchange Event Log and look at the success logs to see the time it takes for the folder type to sync. The value and the sync intervals is at least how long it takes to replicate.
If it is busy syncing contacts, for example, and it is time for Calendars, it will queue up next when Contacts is done.
Both programs do the syncing sequentially, and it is not immediate, in order to take into account any changes.
If you open the Console or stop the service, syncing stops where it is. When you start it again, it will then restart over.