I don't know too much about the in-depth details of the differences between maidsafe, storj, sia, and filecoin, but Sia is the least hyped and my developer friend tells me it's the most solid. I love projects that aren't hyped, especially in terms of investing. That said, maidsafe seems to have the most ambitious plan, so if what they're doing works, it could be a real winner. Storj is hyped. File coin super hyped!