Why would you replicate something that already exists? That's what Evernote has done, with very minimal spin. It's pretty close to empty marketing crud.
A superior solution would be any version control client and regular files. I'm not intimately familiar with Evernote but I'd wager that there are at least ten major features of good version control systems that Evernote doesn't have. Features like decentralisation, transparency, open source, mature security model, mature fork and merge model, commit hooks, etc.
Failing that, even rsync would be a good solution for a single user. I'm sure it's probably more on-wire efficient than whatever system Evernote use.
