+1 from Premium user here too.
Agree with most of the above. The two reasons I find it unusable are:
1. Lag / fidelity is horrible. Just use the built-in Samsung Notes to see the difference.
2. Erasing is difficult. There's a button on the stylus that is used by the built-in app.
Personally, I'd be fine with using a separate app IFF it integrates directly with Evernote. This means that if I click on the page in evernote it should launch the app to continue editing.