Came here to voice my support for backlinking on Evernote. I have been using Roam for over a month now and that capability is INCREDIBLE in the context of linking new ideas together.
IMHO, Evernote with good backlinking support would be a MUCH superior product to Roam, since Evernote already has APIs, good client-side apps, etc...
As it stands now, I'm leaning towards reducing my usage of Evernote for more 'free form' notes based on how seamless Roam is. Will I drop Evernote altogether? Not likely, but I really hope the company recognizes the threat from a new company and doesn't rest on its laurels.