Thanks Craig and YC. Ton of fun.
On the conceptual layer there's a difference in that Sia and Storj seem to be a bit more geared towards consumers and file storage, while IPFS+Filecoin's aim is to be infrastructure in the commons.
(Disclosure: IPFS & libp2p dev)
Either way, thanks for replying. I'm looking forward to reading the new whitepaper soon.