Pre-requisite: These are few steps to be done prior to getting the User Profiles provisioned. Understand the new User Profiles architecture in SharePoint 2010. Few good articles are http://technet.microsoft.com/en-us/library/ee721049(office.14).aspx and...

You create a new User Profile Service Application and try browsing to the Manage link for the User Profile Service Application, this page might fail with the following error, If you filter on the "User Profiles" category in the ULS Logs, you should see...

SharePoint 2010 User Profile Synchronization has undergone a major architectural change. I have attached few articles below which explain this in more details. Now back to upgrade considerations, one of the major concept is the introduction of the "User...