Will this coin have an storage system like Sia's?
yes, it will... you can have a look at the roadmap on the second post here.
Any details of what advantages will it have over Sia's? Sia is cool but is simply a pain in the ass to use their storage.
I don't have the details. I do know that the developer has the file storage working and that it seems to be possible to store files until 2 GB in size.
The Developer is changing the core of the coin atm and is resolving some problems that are appearing with that now. I also know that the whole GUI is going to be changed as we speak, to prepare for the file storage.