I've used a lot of mail systems over the years with the bulk of my working experience being in IBM Notes. In 2017 we migrated to Outlook but fortunately it's on Office 365 (so I've never had to run an exchange server in the office). These days I spend most of my work mail time in Outlook 365 for the web (and my home mail time in Gmail). As pretty much everyone does, I have a love/hate relationship with email. It's still the number one communications system but there are plenty of alternatives and I'm finding myself using those more and more.
Updated 2025
Gmail is my go-to email system for personal use. It's great and does everything I need for now.
Gmail also has a great mobile version. It's fast and it's powerful.
Outlook is the system I love to hate. I have only started to use the desktop version since 2023 when new outlook made its debut. Everyone else in my company seems to hate it but "new-Outlook" is the first version I've liked.
If there was anything I didn't like about Notes, it was mail. I still use the Notes address book all the time because of group nesting and security but I almost never use the mail these days except to redirect mail elsewhere. Verse was great though.
I've used so many alternatives over the years including Yahoo and Thunderbird and various mini-computer mail systems. I've also used a lot of general utilities, such as MailChimp.
There's quite a few alternatives to mail but these are my favourites;
SharePoint and OneDrive: These days we do the bulk of our internal sharing and collaboration using the Share features of OneDrive and SharePoint. We use these features less often with externals but expect that as more people come onto Office 365 that will change.
Microsoft Teams: Teams is our go-to application for meetings these days and COVID-19 has reinforced that. It's become so much easier to get an instant response via teams than via email and collaborating with others on projects using the file and add-in features keeps on getting better and better.
Google: If it's not work and I'm collaborating with friends and family then Google is my main suite. I share directly using Google Drive or if it's a photo, Google photos.
Although I'm very keen on having secure mail software, I really have some issues with using all of the security features in modern mail platforms. I'm happy to use them but I believe they should be nowhere near the front line of defense.
Good mail defense starts with having your DNS carefully configured and protected, with having appropriate DKIM, DMARC and SPF records and with having your MX records pointing to a security service, rather than your mail server. Your mail server should ONLY be talking to the security service and those connections should be point-to-point "IP locked" so that your mail server only talks on a specific port, generally 25, to the registered IP addresses of the security sevice. No other service should be able to talk to your server on that port.
Most of your critical mail rules should be configured within the security service so that your mail server is not wasting resources fighting battles with individual inbound emails. That's not to say that you shouldn't have at least a few rules on your server just in case something slips through.
My current "Go-To" for mail security is mimecast. It's very configurable, has great logging and other features and it engages AI to get the job done. Mimecast also plays quite well with other security software, such as Crowdstrike and Netskope.
Unfortunately Mimecast is quite an expensive solution so if you need to look for cheaper ones, that's an option too. In the past we used Symantec, which then became Veritas and it as okay. Just not as goood as mimecast.
One of the biggest migrations we did was from Notes to Outlook back in 2017.
The software that worked best for us back then was Stellar (which had a lot of configuration troubles but was faster overall) and Kernel, which was easier to set up but took twice the time. Neither was free.
Migrating Mail from Notes and Verse to Outlook - Part 1 - (April 2017)
Migrating Mail from Notes and Verse to Outlook - Part 2 - (April 2017)
I've also used a number of mail services over the years for marketing and alert purposes. Some of the ones that stick in my mind are described below;
MailChimp is an excellent marketing platform that has a lot of great new features. The main thing that you need to do with MailChip is understand the difference between an "audience" and a "tag". Once you have that, things get a whole lot easier.
This is just a facility that allows you to send SMSs from your email system (and you can have replies to those SMSs go back to the organization.