SIA has a practically non existing promotional budget (or they haven't been promoting). I think it's a small team, but they have really proven themselves, and are building a really strong base. As a service, i guess we will see what is most effecient, but it is the most decentralized distributed storage model out there and it's fully operational.

Right now they are building up API's and creating more usability by enterprise applications (like amazon server storage). Next feature on the stack if i'm not mistaken is shared storage (drop box, google drive) but might be more along the lines of shared downloads at the moment.

The cost of storage is bid on by the "farmers", the nodes providing storage space, they try to outbid other farmers by reducing their fees and proving their reliability. The price of SIA doesn't depend directly on cost of storage. However the network-wide total used storage as well as the Capacity/used ratio does affect price as the SIACOIN token is integrated into the contracts between the farmers and the renters. SIACOIN gets locked up in agreements for months! As the network gains users, the price will go up drastically, because not only does it take sia to rent storage, it takes sia to farm storage. Farmers must place collateral in contracts in order to assure renters financially that they won't break their contract (supply a service of cloud storage). This promotes healthy nodes, as a network creating a working service.  The farmers recieve their own collateral + the renters Fees at the end of the contract.

Essentially each node will have large chunks of SIA locked up much like a masternode, but proportional to the amount of disk space they provide.  It might be a some months down the road, but SIA is on course to boom in my book. I think i just convinced my self to buy more (yikes).