Delivery Monitor has been a great tool. It shows how much email is delivered by a bunch of ISPs - probably more than even needed. Unfortunately it looks like it is closing it's service so I'm searching for a replacement. Return Path looks good too but looks like it is aimed for bigger businesses and is really really expensive. MailMonitorApp.com looks pretty basic but is very reasonable and has a free trial so I think I'll give that a shot. Sorry to see Delivery Monitor close its doors.
An inexpensive way monitor email delivery - As a website owner, getting your emails delivered can be difficult and expensive. Companies like Return Path offer very expensive ($10k+) email monitoring and delivery services. They will both telll you if your emails are reaching your customers inboxes and help you to increase your delivery rates. However, for a start up or a small business, these services are often too expensive.
This is where Delivery Monitor comes in. It offers a very simple service - it tells you if your emails are being delivered to major ISPs and email services. And it works for this, very well. However, Delivery Monitor does not help you get your emails delivered - this is still up to you (and can be the hard party if you are not technically savvy). However for $80 per month, Delivery Monitor still feels like a good deal. Especially because you have 30 days to cancel so you can try it out for free (and if all your emails are delivered, you may not need it again!).