Quote Originally Posted by Dragonbite View Post
  • Ubuntu one allows your folders to be synchronized from where they are (~/Documents instead of ~/Dropbox/Documents, etc.). Either Sugar Synch or Wuala are the only other services that do that, and that is Windows-only.
  • Ubunut One includes Windows client (and Windows XP too). This client synchronizes the actual ~/Document folders in Windows (instead of ~/Dropbox/Documents) like Ubuntu
  • Dropbox is $20/month or $200/year for 100GB while Ubuntu One is $3/month or $30/year for 20 GB or 5x$3=$15/month and 5x$30=$150 per year for 100GB.
  • SkyDrive, Google Drive and Amazon's Cloud Drive do not include Linux clients.
  • Ubuntu One automatically receives music purchased from the Ubuntu One Music Store (not that many use it)
  • Ubunut One has optional music streaming with Android/iOS clients.
  • Supposedly pictures taken by a smartphone with Ubuntu One can have pictures automatically synchronized with Ubuntu One, but I cannot confirm that at this point.
  • Files synchronized can be easily pulled down after upgrading or clean-installing a new or over an existing Ubuntu installation.

That's all I can think of right now.

If cheap 100GB is required, Microsoft's SkyDrive is the cheapest ($.50/GB/year, or $50/year for 100GB). Plus if you have a Hotmail/Live account before April you can get 25 GB for free, otherwise you start with 7GB which is more than the others.
I've decided to go with Google Drive simply because it is so much cheaper and the only negative is the lack of an official linux client. Google has said a linux client is on the way.

That said, there is the open source Grive client for Google Drive. Its has fully working 2-way sync but is missing the ability to watch a folder for changes. However, I'm fixing that today and will hopefully contribute it back soon.