I'm in the process of moving my email from gmail to Fastmail and it has been really great. I think they must do a lot of the interface locally in Javascript because it is really fast. I had been thinking about switching for a while because recently Google Sites forced me to migrate to Sites V2 and it was really bad. I thought, "If I ever had a problem with my email, there is no one at Google who would help me." Whereas at Fastmail, I have sent in several suggestions and questions and they've responded to each one.

Here's the process I'm using, for anyone who might be considering it.

Fastmail can copy all your past Gmail to your new Fastmail account. I didn't do that because I'm planning on keeping the Gmail account, so can get to past email anytime I need it, and it's mostly old junk I'll never need again (I'm only using about 3GB out of 30GB for a free account). Also, if you have labeled email, each label on an email causes it to be duplicated at Fastmail.

Fastmail can be setup to fetch your Gmail with IMAP every 5 minutes or POP your email periodically, with or without deleting it from Gmail. I tried that, but it appeared what actually happened is that it fetched Gmail only when I clicked on the Inbox. Which is fine, but I liked how Fastmail changes the browser tabs to show when email is received, and that didn't work right (I waited 20 minutes and it never indicated there was new email.)

So instead, I set Gmail to forward mail to Fastmail. Because I had both business (HashBackup) and personal email going to the same Gmail account, and wanted to separate the two at Fastmail, I had to use some tricks. Gmail normally only forwards email to one email address, and I wanted each Gmail to be forwarded to 2 Fastmail addresses. To do this, you have to use the regular forwarding mechanism for each Fastmail address separately, to authorize your 2 Fastmail email addresses, then disable it altogether and use 2 forwarding filters at Gmail. On Fastmail, I just delete the redundant email. It's a lot easier than routing Gmail to 1 Fastmail address and then forwarding it to the other Fastmail address, and each email looks like the original at Fastmail rather than 1 looking like a forwarded email.

With Gmail, I was letting messages age and accumulate in the Inbox. To make it easier to see new Gmail that might be a straggler service I need to update, I enabled the Javascript Gmail interface, selected all Inbox messages (18K!) and moved them to the Archive folder. (Then promptly disabled the Gmail Javascript interface because all those icons make it impossible to use!) So old email is still available for searching if I need it, but it isn't cluttering up my Gmail Inbox. On Fastmail, I'm trying out keeping my Inbox clear and trashing emails after I respond. I have it setup to automatically delete Trash emails older than a year (you can leave them forever if you prefer).

To let people know about the switch, I added a Gmail vacation message that says "I got your email, I'm changing email addresses, for personal use blah, for business, use blah". That causes a bounce once in a while, but Fastmail puts those in the Spam folder.

Then, as I have time, I've been signing in and changing email address on various services I use. There are about 40 of these.

With a custom domain account ($45/year for 2 years) Fastmail also has options like hosting a static website and using your storage as file storage with FTP or browser uploading & downloading. I'm not using that, but coming from Workspace, it might be something you need. I just tried it out, and it's nice! I uploaded a file to my file space, it defaults to private, and you can create a special link to share the file with others. I tried doing this with Apple iCloud last night for some server photos and couldn't make heads or tails out of it, but with Fastmail today it was easy. Fastmail will also host your domain name, so you don't need to mess with a VM somewhere. I'm using Linode to host my domain because I need a VM for other HashBackup-related stuff.

Fastmail has Notes and a Calendar too, but I haven't used those. I also haven't downloaded the Fastmail phone app, but if it's anything like the website, I'm sure it's nice too.