I have been facing the problem with my sharepoint user profile synchronization service for almost 2 months.
I have followed exactly the http://www.harbar.net/articles/sp2010ups.aspx article and yet having problems.
The user profile service is running fine. I am using the farm account to start the user profile synchronization service. However, it takes around 5 min saying "Starting" and then stops.
While starting, I followed the "Windows Services". I noticed that the "Forefront Identity Manager Synchronization Service" once starts and then stops, before the User Profile Synchronization Service stops.
The sp_ups account has been delegated "Replicating Directory Changes" permission and the farm account is also a member of administrators group and has the permission to log on locally which tells that I do not have any permission problems.
I have also installed the February 2012 hotfix but no luck.