http://industrymailout.com http://industrymailout.com is my vote. We use them quite a bit for numerous clients and haven't had any problems. Anything not presen

http://industrymailout.com http://industrymailout.com is my vote. We use them quite a bit for numerous clients and haven't had any problems. Anything not present in their back end, they've built in. Anywhere from 1000 - 35000 mails without a hitch and an API.