That is exactly our experience with the development of Metric Mail.

Yes, there are limitations. And most of them might get you upset first, but if you "work with the rules" it is a fantastic platform.

Metric Mail has been running absolutely fine since its launch in August, it has never failed us. Even under severe traffic it scaled without any problems.

We knew from the beginning what the limitations are and this way there were no big suprises during the development.