Feature Set:  

When you set up Allmydata, you can choose to automatically backup some common files including My Documents, My Music, My Pictures and My Videos. Also during setup, you can specify exactly how much of your hard drive you want to share and see the equivalent of how much online space you will receive.

Security:  

Allmydata uses SSL encryption during file transfers and storage. They utilize peer–to–peer architecture and then "layer services on top of this (like backup)."

Storage Space/Price:  

One of the biggest advantages of Allmydata is the price. If you want to store stuff from your iPhone, Allmydata has a plan that gives you 1 GB of storage for $10 per year (not per month), which is a pretty awesome deal if you don't have much to store and you need online storage for your phone.

If you need more space than that, Allmydata has a plan that gives you unlimited storage space for $9.99 per month (although this doesn't apply to the iPhone).

Despite the fact that these prices are pretty good, they definitely aren't the best. And Allmydata doesn't have a free account like many other services do. If you want free accounts or cheaper storage, try one of the top three services, like SugarSync or Box.net.

Ease of Use:  

You have to download and install a client on each computer you will use to access your files. Once the client is installed, Allmydata is very easy to use and opens just like a normal drive. You can easily drag and drop the files you want to load onto the virtual drive.

The only way to share files is to give your friend or family member your user name and password so they can access your account.

Help/Support:  

Allmydata offers a lot of help and support to their clients. Self help features include user forums, FAQs and tutorials. You can contact customer service by phone or email.

All my data offers a lot of storage for a little money. This is a good concept but it's still not as good as some of the services found in the top three products.