I have been using Outlook for the longest time and have tried FairEmail a couple of times and simply deleted it. Tried sticking through it for about a month and I'll be sticking with it for a good long time now :)
I use ProtonMail. Additionally, i have set up e-mail aliases with my domain - i get e-mail addresses like kbin@mydomain.com, or personal@mydomain.com. Its quite useful when i suddenly get sent a bunch of random spam e-mail.
I can then just block that e-mail from receving e-mail, its quite handy.
Thunderbird on the desktop, Aquamail on Android, RoundCube/SquirrelMail via the web in a pinch. Back in the day I also used Evolution on Linux (when T-bird was buggy and lacking some features). Despite having many email buckets in the cloud, I keep no mail in any of them. I've self-hosted since '99, so I've been able to do whatever.
I did use Outlook back in sepia times (pre-'98) and used Pegasus and/or Pine before that. :p
Edison. I use it on my Pixel, iPhone, and iPad. It has some more advanced features I don't use, it just has a simple, straightforward UI on iOS and Android and doesn't hassle me too much about upgrading to paid features.
Used Gmail for a long time, 2 weeks ago switched to Outlook and simply amazed. It's easy to use, doesn't show you any ads unlike Gmail. And keep tracking the mails is much more enjoyable compared to Gmail. I believe it can do more of that if rules can be applied to Google mail accounts.
I used AquaMail for years, but they just decided that this fall they will go subscription, and old paid users who bought the app will not get all features. So, I've transitioned to the paid (one time purchase) version of Nine email app(by 9folders). It is equally capable, working with my free accounts and my O365 corporate account (including synching calendar). I looked at several open source options, and none were competent to deal with my Work O365 stuff.
I've migrated from just using a gmail account to using Anonaddy which point towards a Tutanota email. The migration was PAINFUL, but glad I persisted and went through with it.
For Gmail users on Mac desktop, I really can’t recommend Minestream enough, if a paid app isn’t a dealbreaker. It’s designed by ex-Applers and implements gmail’s API completely— even to the point of the signature editor and vacation auto responder and having a mode that only shows unread messages and starred messages in your inbox (which is kind of a badass way to stay on top of busy mailboxes).
Been using mutt for years, and I still love it. But getting it to works is more and more of a pain nowadays, and I find myself using whatever webmail my company uses (right now O365).
For personnal emails, mutt on the desktop, and a selfhosted roundcube for when I don't have a client.
Careful if you're using Outlook on Android. From what I've read, it doesn't actually locally handle non-exchange accounts like IMAP or POP3 (why are you using POP3 though). It's done on Microsoft's servers, so your basically giving Microsoft your e-mails. I'm not sure what kind of access they get to them from the privacy agreement you probably just clicked past.
So Outlook in Android users Microsoft servers to fetch your mail, and the client just shows whatever the server got.
I started using Spark late last year. It's simplified my mail handling quite a bit. There's also a desktop client for Windows, Dunno about OSX and IOS.
Also using outlook. I can say for certain there are some bugs with IMAP email accounts, but other than that it has been working well for me for years.
The only thing I don't like about it (other than the IMAP bugs) is the notification sounds that are exactly the same as my work mail on PC. I get jittery whenever I hear those sounds.
I used outlook for years. Then they threw ads in between emails... I instantly deleted outlook and haven't looked back. The last place I want to see ads is my fucking email 🙄
On my desktop: GNOME Evolution - but only because my university uses Outlook w/ Exchange (cringe) and the UI is slightly more tolerable than Thunderbird.
On my phone: I just use the baked-in Samsung Mail app.
In terms of provider, I used to use Gmail for my personal, but got tired of Big G scraping my correspondence. I tried Proton, but its integration story is a complete joke (you can upload your calendar and contacts but there's no DAV support, their IMAP bridge is a non-standard-compliant dumpster fire that doesn't work with half the clients I tried...) so I ended up on Fastmail.
I use Tutanota's clients, and enjoy it. Haven't had any issues, was a great replacement to the unencrypted privacy-invasive Gmail and Google Calendar, sorting to folders has been even more convenient
Work Desktop: Microsoft Outlook
Work Mobile: Microsoft Outlook
Home Desktop: mail.google.com
Home Mobile: GMail android app
Why? Because I was on Proton personally for a long time but got frustrated with the lack of features and also my wife and I rely heavily on shared groupware stuff like calendars and reminders, so we switched back to Google Mail. Once Proton is a bit more feature-rich, we'll take a look at it again.
I'm moving to Tutanota so I have to use there client on desktop and mobile. I have Thunderbird for my Gmail and Outlook emails on Desktop and just use Gmail and Outlook apps on my phone.
I use Em Client on desktop and I love it, on android the Em Client app is still in beta and quite unstable so for now I'm using outlook. Looking at the comments I should give K9 a go.
Although my main one is gmail, I have been using proton mail for a while and I'm getting to point where I trust it for most stuff and I will start to move non-critical stuff away from gmail.
on desktop I use eM Client. On Android I was using just plain GMail but I saw people in this comment section using other stuff so I checked it out and swapped to FairEmail.
edit: FairEmail is fantastic and I've upgraded to pro. Definitely recommend this one for mobile users with multiple email accounts.
Used to use Thunderbird but I wanted something that just looked like it was from this century. I like how eM Client works and its features and it looks nice. I don't like that I am limited to 2 email accounts though. I'd love something like it that is FOSS and allows more email addresses.
Just remember what the Magic 8-ball says when you drink the water inside it… "Outlook is not good!"
Really, though, I know the 'me' of about 20 years ago would be shocked to hear this, but the whole Microsoft suite with Outlook is pretty comfortable to run and use. I use it when hosting websites for my business, and it's always worked how I needed it.
Beyond that, I used Thunderbird for years and that's my go-to client when I want to go free. It's easy to set up and people usually love using a Mozilla product.
Every time I try a different email client (on the desktop) I always go back to Thunderbird within a few days. Within the last few months I've grown to love a T-bird fork called "Betterbird" which seems a lot snappier and more responsive than the "official" bird.
I actually swapped to Protonmail last night. Took awhile to change the email address on everything, but worth it. Trying out the free version for now, keeping my Gmail as a backup and for Android.
Used Eudora long ago. As its support dropped and Qualcomm's development of Thunderbird took off, somewhere during that I embraced the spiritual companion of Firefox. I have to use Outlook at work, that helps me not consider changing at home. Also jumped on the Gmail bandwagon back when you had to get an invite to participate. It was just a side email at the time with storage built in, but when my original ISP provider finally threatened to charge me for having an email account, I moved everything over and linked Thunderbird up to pull from Gmail.