I think its worth having a listen to this:

http://www.theblockchainshow.com/43-kevin-hobbs-of-vanbex-group-and-etherparty/

Kevin Hobbs CEO responded in an AMA session in Slack and Telegram.

He had a brief look at Blockcat (on the spot) and he says it looks like its just on way. There are no other parties allowed in the contract. They are only holding funds.

No oracles to execute contracts

He will have this team do a comparison to be more precise on the differences.

Its probably best to join the Telegram channel, they have hit over 100 members!