I’ve recently fallen down a rabbit hole into a land of email clients. Two requirements I have are:

• Scheduling an email to be sent at a specific time. I’ve found that if you’ve completed work early for some clients it is often best to keep to the agreed schedule for completion so I will write the email and schedule it to be sent a day or two later. I work on many projects at the same time and when my blocked time finishes for a client I schedule non-urgent emails for the end of the day so I don’t get interrupted with a reply when I’m doing something different.
• Snoozing emails. This is less important, but useful for maintaining focus and quickly pushing an email to a time when it makes sense to act.

A few weeks ago one of my email accounts was down and Spark kept taking focus every few minutes with an error dialog to tell me there was a problem - not a boon for productivity at the time.

I gave Mailbutler a try, however after a few days it started hanging Mail.app on launch (it’s a plugin to the default macOS mail client) - potentially the flaky email server, but not something I was willing to work through given the monthly cost ($9.95/month if you don’t want a watermark added to your messages.) To be fair they did email back a few days after I cancelled my subscription saying they had a potential fix, but by that time I had moved on.

I decided to give Spark another go as the email server that was causing issues seemed to have been resolved. However, I then had an issue when send later caused the app to repeatedly crash after 30 seconds of launch until I deleted the offending message. It was a short message with a small (<100KB) PDF file.

Next I looked at the mail clients offered as part of my Setapp subscription - Canary Mail and Newton. It turned out Canary Mail doesn’t support send later, and the Newton UI just didn’t work for me.

Then came Airmail. Despite lots of people saying how much they like the UI, I’m not that keen. However, the main issue was trying send later and the message just disappeared - no idea if it will send when I scheduled it!

Finally I gave Postbox a try without having read through it’s feature set. It turns out it doesn’t support send later or snoozing emails. So despite its nice colourful UI, it was a definite non-starter.

So I’m back to Spark. It is free if you aren’t using teams features, is frequently updated, and has an impressive feature list with a pleasing UI. As a software developer myself, I know how impossible it is to write bug-free software. Having surveyed most of the other macOS mail clients, I’m thinking Spark is likely to remain my best option unless something completely new comes along.