I especially agree with having a real in-app page for gathering feedback. When we were building Flowdock, one of the best things early on was giving the users the simplest possible tool for giving feedback: a single text field (just like you have). Even though this is a little more work than just having a team@... email link, it does have some great benefits:
- Full control on where the feedback gets sent and who/what gets notified (requires some backend code of course)
- Easy for the user, no extra logins or weird popups
- You can send extra information like the browser's user agent string along with the message to help resolve some issues
PS: The last link in the article ("follow me on Kippt") should link to https://kippt.com/jorilallo :)