The only downside of user echo is the topics are sorted by number of up votes by default.
That causes new threads to get lost, take a while to get seen and loose input.
Fortunately that is a setting which can be set by the forum admins:http://feedback.userecho.com/topic/5427-is-it-possible-to-change-default-sorting-type-as-for-forum/
If user echo sorts topics by Last Updated by default the it would work exactly like the forum, but with notifications, votes and better design.
Then just prevent new topics in the forum and leave it for reference.