So I was sceptical, read so many horror stories on various forums so much so I held back activating my iP4s for 3 day lol. I made the transition from MM to iCloud yesterday - I have an iTunes id and an MM id. I switched from Snow Leopard to Lion (other than iCloud can't see a huge difference) Backed everything up first; contacts onto desktop as well as iCal then switched from MM to iCloud which was so simple. Then activated my iP4s to iCloud - using my MM Apple id. Almost instantly I could see all my contacts, calendars and emails on both my mac and iP4s. Of course I had nothing in my Music folder on my iP4s so I logged in with my iTunes id in settings, store and then downloaded all my purchased tunes, apps etc. Only thing that sort of hit and miss was Twitter notifications but that now appears to be working as of today. So, make the change, have faith .... it will work !!