what's the latest update regardin Elrond NFT marketplace and what's the difference between that and the existing ones? From the existing markets, which one do people prefer the most? Trust Market, Dead rare, Elrond NFT Swap, Isengard?

There isn't any new news regarding the Elrond NFT marketplace, but people tend to think that it isn't far away. We don't know whether it will somehow have more than community NFT marketplace projects already in existence. Your question on preferences seems best asked in the Elrond NFT Lounge group. Also, it's easy to form your own opinon about it by visiting and browsing each.

Trust.market new updates are cool

Probably Isengard