Mailbutler is great for people who want to practice "zero inbox," because you can "snooze" emails for later response or action. The task feature is also very useful, as it allows me to make note of what action needs to be taken in regards to each email. In general, it helps me be far more efficient in my email communication.
It fills the gap between large commercial softwares for large companies, and for small companies. Most email hosts are just basic until you start bringing in video calls, chat, etc. Missive has that and more, and I think is the #1 email choice for small companies.
Mailbutler occasionally conflicts with other macOS Mail plug-ins. Though, in most (if not all) cases the issue tends to be with other plugins.
The Mail app for iOS/iPadOS doesn't support plugins, making it necessary to use Mailbutler's own app to access a limited subset of the functionality on macOS/iPadOS.
I'm not aware of any other products that provide the same functionality within the macOS Mail client. There are some third-party email apps for macOS and iOS/iPadOS that have some of Mailbutler's features, but my preference is to stay with Apple's Mail client, partially for security reasons.
I can only compare to free services or to Outlook. I cannot go back to Outlook... Truly. Outlook hits all the right marks for a business, and Missive exceeds those marks and sets new standards. I joined a company that had already chosen Missive. I not only was able to pick it up intuitively, but I felt proficient at it within a couple of weeks and already felt my workflow and communication skyrocket.
The Delay Send feature has improved my email communications by allowing me to add details or make corrections before the email is actually sent to the recipient.
Being able to track emails has been very helpful and, in some cases, has prompted me to contact people through an alternate communication channel (e.g. phone or text).
Overall efficiency in our communication has probably tripled. We can draw a collaborative conclusion, in-office or remote, desktop or remote, within minutes assuming we are all available.
We realize we are still "under-utilizing" this app. It can be a powerhouse if mastered.