I have used mailchannels in my work as an email system admin of large organizations. The customer service is excellent. They really care about their customers, and they are always willing to help you out with any issue that you may be having. There really isn't anything wrong with this product. It is easy to use, and it works well. I recommend using them because they are honest, friendly, and helpful. We were looking for a solution to block certain types of domains from being able to send emails through our domain. This solved that problem, but we also wanted to know what was happening when people tried to get around the blocks. Mailchannels offered us that feature.