I am having the same problem with my iPad (fourth gen). My iPhone 4S will sync notes in iCloud, but the iPad will not. Initially, I was using Gmail as my account for syncing notes, but I now want to change that to iCloud. I did not initially have an iCloud.com email address. I set one up yesterday and my iPad is detecting it for facetime and iMessage, but not for notes or email. I want to use the iCloud email address for notes so that I can then remove them from my Gmail.
I was about to adopt the solution set out above to clear the problem on my iPad, but it warned me that I would delete the content of my Photo stream from my iPad. I do not wish to do this! I realise that the content of the Photo stream still be available, but will my iPad be able to access old photos that were taken before I deleted and reinitialise the account, or will it be just be new photographs(i.e. those are taken after I reinitialise the iCloud account on my iPad) that go into the Photo stream on the iPad?
If this will affect my ability to use photo stream and access all photographs, is there an alternative method to get notes to sync through iCloud on my iPad?
I appreciate any and all help that anyone might be able to provide.