Adding some information about those two token, you can visit the link provided below.
Storj is currently rank 105 in coinmarketcap, and Siacoin is rank 36. They have at least 30 exchanges site, famous and non famous.
Storj - https://coinmarketcap.com/currencies/storj/#markets
Sia - https://coinmarketcap.com/currencies/siacoin/#markets

But I expect that this Casper API will be more dominant in cloud based data storage system, this one is more advance on those two.