Bad configuration, bad business concept, very unreliable.

Update - 08-Mar-2016:
Mailtones seems to be all but defunct at this point. Messages sent to the address dont go anywhere, arent forwarded to the device, etc. It appears that this app/developer may be defunct, as the app relies on their third party servers, which no longer seem to be forwarding mail.

21-Nov-2015:
Use of this app requires you to forward your emails (in their entirety) to a third party mailserver. This is obviously a security issue for most people, exposing their emails in plain text to third parties.

The real problem though? They host their own mailservers, this has a monthly cost obviously. Since the app is a one time fee, you can see where this business model fails, selling a one time product that has a monthly upkeep on their part. As a result, the service has gone steadily downhill. I use this for pager emails (as 1 of 2 methods), and the emails are frequently delayed between a few minutes, to a few hours, rendering the service useless.

Long story short, unless youre dont care about the emails youre receiving, having third parties with plain-text access to all of your communications, or having stuff delivered in a timely manner, youd be better to find another solution.

porcupine5 about MailTones - Pager Alerts for Email and Gmail, v1.60