The previous account was not a MobileMe account prior. Also, it has been syncing perfectly fine for the past two years with Mountain Lion, Lion and iOS 5 up.
As far as getting the data from when I got to counter the other it's not a simple task. You have to make sure you go into each of your apps that currently use documents in the cloud and turn off documents in the cloud for each of the apps. This way, when you remove the iCloud account from settings but it will not remove the associated data from each of the apps. In other words, before you remove the old iCloud account, by turning off documents in the cloud for each of the individual apps The data contained in iCloud documents should be converted into local data within each application. Then after you delete the account and sign in using the new iCloud account go back into each of these applications and turn iCloud syncing back on. This will force the app to move the now local data into the new iCloud accounts document sync sandbox.
The thing to be particularly careful about is making sure that the applications that use documents in the cloud are no longer set up to do so before you remove the old I cannot account. Because when you remove the old I cannot account it will delete all associated documents in the cloud from the device. However, if you have already turned off documents on a per app basis the data contained in iCloud will have already been moved into the local sandbox.
As an added safety measure I would first try to export the data in anyway possible for each of the applications. If the application offers some way of getting your data out of it such as emailing a backup archive make sure and perform this routine as an added safety measure.