My reasoning was that most people only have one email account and thus would be fine with the free version.

As to why in-app purchase, I wanted people to be able to use it first without payment. In-app purchase has been growing in popularity on the App Stores lately and I think this is why. I also feel it's cleaner not to have two separate versions on the App Store.

But thanks for the feedback, I guess you're right. It's misleading to call it free. I will amend the landing page to make it clearer.

There is no use of IMAP, it's using the Gmail API. It does poll the Gmail API frequently which is currently the recommended method of checking for new email according to Google.

I know at some point they will switch to PubSubHubbub as the preferred way to get notifications.