We've been loyal Campaign Monitor users for well over 10 years (!!), and in that time, we've always found it to be incredibly easy to manage our clients as sending organisations under ours.The other 'killer feature' is the email builder. It's gone through a number of changes over the years. Still, fundamentally it has always remained effortless and intuitive to use, making custom-designed and responsive emails simple to put together.We've tried a bunch of other platforms over the years as clients have come to us with their existing tools, and I can safely say there's no other email platform that comes close to the UX. 👏