Plus, isn't photostream both limited to the most recent 1000 photos AND is non-permanent storage? Any photos you wish to keep must be saved manually.
It is unless you have a Mac in which case it automatically syncs all your photos to that.
http://www.apple.com/icloud/features/photo-stream.html
I like it as it means I have my last 30 days worth of photos always available and they automatically available on my MBP.