Hey Ugg,
I downloaded and installed the crx for the Chrome version, it doesn't pop up a window to select a local filesystem for me.
Yeah, I didn't know Google doesn't accept extensions accessing local files, it's definitely a pain. App adoption is pretty hot on the Chrome Store, my apps on there has 300-40,000 adopters.
I can't view html and any other type of files either in the firefox version, added an issue.
If you want to turn this into a web app, NimbusBase is also an alternative. Instead of accessing local folders (which I actually think is better than evernote), you can have it directly like evernote and create new entries and store the binary on Dropbox or GDrive and the metadata in NimbusBase data structure.
But I think your native bindings are definitely the strong point of the app, and you should probably get more users by building html5 native apps with native wrappers on Win/Mac.
https://github.com/adobe/brackets-shell is a good one.
Ray