with apple you can get 155GB per year for $100. (includes 5GB free)
with dropbox you can get 152GB per year for $120.(includes 2GB free)
apple doesn't charge for music, apps, photostream pics against your free 5GB, dropbox does.
Umm, no you can't. Please read the OP again. Dropbox's upgrade plan offers you twice as much storage space as Apple's for the same price. I won't go into ancillary benefits, but just going by raw data storage of your choice, then Dropbox offers much better value for money.
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I'm curious about iTunes sync. I'm waiting to find out whether it will honour local metadata or if it will just impose itunes' default tags on my library. If it's the latter that would leave me very underwhelmed as I have a very large music library that I've spent a long time customising. I prefer to have a relatively small number of genres, with things further broken down using the Grouping field. If iTunes match undoes all that it will be next to useless for someone like me, so I'm really keeping my fingers crossed.