Sia is not more advanced than Storj, they are different, each has its strengths and weaknesses. Storj is faster, easier to maintain and scale and easier for individuals and companies to use , Sia is more decentralized, does not have a single point of failure and you could thus argue that Sia is more secure than Storj. Sia is also not dependent on a centralized bridge like is the case with Storj. So different technologies. We will see who comes out on top.
Stengths and weaknesses are discussed in the article. Have you read through all the comments? Storj has more weaknesses than Sia.
If you are too lazy to read (as you apparently seem to be), skip to the comments between
Taek and
super.