Been using Spideroak for over 2 weeks now, and Spideroak seems comparable to Dropbox in almost everything, with the approach adopted by Spideroak slightly safer and user customizable. More details on what they do can be found for spideroak here and dropbox here. I shall discuss the pros and cons from my (read: user) perspective.
Similarities
Automatic backup + versioning
cross-platform (mac, linux, wins). So no problems here.
Ability to share folders
Web Access
Differences
Ease-of-use – Dropbox is easier than Spideroak, simply because dropbox has less functionality and is less customizable. Spideroak has 5 tutorials, while dropbox only has one.
Syncing procedure – Dropbox requires you to drop the files you want to sync into one specified folder, which changes the structure of your files. Spideroak allows you to specify the files you want to sync through a normal window dialog. This really depends on the way you work. For me, i like dropbox’s method better because everytime i need to sync something, i will just click and drag the folder into dropbox’s folder, and it will sync. Spideroak requires you to fire up its dialog and check the folder you want to sync (although you could always specify a folder called “dropbox” or whatever you want to call it which is set to sync in spideroak and do the same thing).
Sync versus backup - Spideroak differentiates between sync-ing and backing up files. no difference to me though.
Zero-knowledge protocol – Spideroak uses Zero-knowledge protocol, which means that no one can access your data. more information can be found here. Dropbox does not have place much information on this on their website except the fact that its AES256. More information can be found here. Again, no difference in my opinion, as i wont trust the company anyway, and if i have something really really top secret, i would mount my own encrypted image, using Leopard’s disk utility or Truecrypt.
Pricing – Spideroak’s pricing is a lot less than Dropbox’s pricing.
Verdict
If you are just looking for some online backup of some documents that you have, or online syncing of some documents which you are currently working on, AND your files are less than 2GB, then you’ll be fine with either dropbox or spideroak, although for a gentler learning curve, dropbox is the one (although spideroak is really really easy to use as well).
If however you are looking for a complete solution, or your files are super duper kill-you-if-i-tell-you kind of secret, and your files are more than 2GB, then definitely you will have to go for spideroak, for its Zero Knowledge protocols and cheaper price.
Posted by throwyourchalk 
Posted by throwyourchalk 