SMTP was the setting in 6.0 - I am guessing it is because some SME servers send mail through their ISP's mail server because they're on a residential/restricted connection, and sendmail doesn't handle that? I dont know...
I believe the vfs settings are also unchanged from 6.0 - are their other horde apps that require or work better with your settings? Or is using mysql for this supposed to be faster/better?