SparkPost&#x2F;MessageSystems claims to have the highest inbox rate in the space, and their customer list backs this up. It&#x27;s much more impressive than Asana, Desk, and Minecraft (think LinkedIn, Facebook, Zillow, Pinterest, etc).<p>They absolutely recognize that ESPs are a commodity, even reselling delivery to ExactTarget, Responsys, etc, as the &quot;pipe&quot;. It&#x27;s hard to believe your reasoning when the industry leader is saying something different.