I cannot speak for Storiqa as my understanding as it is a crowdsale for something that we released in July of 2014. Syscoin released the world's first decentralized marketplace then and we have been working hard at developing it for ease-of-use and accessibility for the last 4 years.
With regards to Bitbay, our approach is very different from my understanding but I do not actively follow them. We strongly encourage any innovation that can be made in this space as it can only help everyone. Here's a few differences to my knowledge.
Syscoin:
Blockchain-Based decentralized marketplace(we strongly believe that this is the best solution, coupled with masternodes and if properly harnessed like our protocol, the blockchain can do much more than just send and receive funds).
Decentralized escrow (the buyer and seller have to trust an arbiter if they want to use escrow service), it is not mandatory.
Team: We have Sebastian Schepis, Jag Sidhu, Dan Wasyluk & Willy Ko as our core developers and we have been working with many contributors as well. We also have a marketing and PR team working on propagating the word about Syscoin.
Partnerships: Syscoin and our company Blockchain Foundry Inc has been a partner of Microsoft for almost 2 years
https://www.coindesk.com/press-releases/syscoin-official-microsoft-azure-development-partner/ ; We have also been members of the Decentralized Identity Foundation for almost 1 year:
http://identity.foundation/ . We are also Supernet partners.
Bitbay:
Peer to Peer based marketplace (Like OpenBazaar).
Double deposit escrow (the buyer and seller need to deposit double the amount, both lose the amounts if there's a problem with the transaction).
Team: My understanding is that they have one developer David Zimbeck, this can jeopardize the project if something happens to him.
Partnerships: Everything I could find was with relations to BitBay, the exchange and not the currency.
One comment is that since a huge exchange is already called Bitbay and has been trusted for many years, the fact that they decided to call themselves the same name really leads to confusion every time I try to search for them; I assume this would be the same for potential partners and investors that are looking them up.
DYOR(Do your own research) as they say, we strongly suggest you join our Slack, you can DM me your e-mail address and I'll send you an invite.