I'm shocked this product doesn't have more reviews. Have to offset the one negative review with a positive.
I've been using Mailtrack for a year now. Prior to that I tested many different online tools to track email from Gmail and none worked well enough for. HubSpot's SideKick worked wonderfully, but then became more complex as they integrated it into their CRM.
For me, I want simplicity. I want to know when my emails were read. That way it saves me the guess work of the email being delivered and read.
I highly recommend using Mailtrack and purchasing the Pro version! It's worth the minimal cost.
Don't undertend why they want access to all our emails - inbox and outbox and other email trackers works well without that.
Sadly I have to admin that most of the times it doesn't work well and returns "Sent without Mailtrack" instead. This happens both for me and my colleagues.