EmailDelivery.com

I bought this EmailDelivery.com when they were first on appsumo and refunded almost immediately because I didn't understand how to set it up. I regretted it almost immediately.

When they came back to appsumo, I bought it, and this time, I paid someone $30 to set it up for me, now I save $300+/mo (maybe more) on email marketing.

I still have a regret... I wish I would've bought Tier 3.

So far, I am pretty happy with the support; they respond in a timely manner (~24-48hr).

Note: if you are someone spending hundred maybe thousands with ESP (ie Mailchimp etc).