I moved to iOS 5 and the iCloud (from MobileMe) a couple of weeks ago and have a few observations.  Along with iCloud comes the PhotoStream which distributes across all of your enabled devices the most recent 1,000 pictures that you have taken/imported.  I am able to use it on my iPhone, iPad, iMac, MacBook Air and Apple TV.  It works very well and the only issue that I have experienced so far is confusion as to whether to use my original iTunes account or my me.com account.  As far as I know Apple has not implemented a means of combining the two accounts so users need to be aware of which that they are logged in as.  This is particularly true when buying things via the App Store because you may end up in the situation where some things you have bought are available via one login and the rest the other.   I think that vendors of streaming photo products (like Ceiva and Kodak) will be considering providing access to iCloud PhotoStream facilities as part of their offering.