Hey Edward,
We are Cloudwords users and it is pretty impressive. We tested it for Marketo specifically. You can reference an email already created in Mkto, then choose a vendor based on price, and once comleted, the integration will put the translated email within it's owner folder within the folder the original email is housed. Formatting stayed true, the translation seemed to be spot on, and it helps build up your translation memory.
We decided that we didn't have a need for the Marketo integration yet, the demand wasn't there, but we did get it for managing our collateral like WP's. You have to buy a higher edition to use internal translators, someone from within your own company, but we struck a deal with a vendor to help facilitate. I am not involved with its current use, but everything I have seen about the product has been great.
Hope that helps!