The ability to easily manage multiple customers, campaigns in one dashboard is awesome for our customers! It allows us to focus on core business needs instead of managing emails from different platforms like mailchimp etc. I would definitely recommend using such tools as this saves time for you and your team members. Some features have been confusing at first but we are able to figure it out if we spend some extra effort. We are solving email problems which were causing customer churn so far by switching them over to sendgrid widget (and sending from there). The ability to track opens, clicks & unsubscribes is great! You can also integrate with MailChimp or AWeber for additional features like auto responders etc. I wish there was more flexibility in how you could customize your widget as well (e.g., color scheme). This would make it easier if someone were looking at multiple companies/services from one place instead of having two different widgets up front that are not linked together yet have similar functionality but slightly differ by look / feel.