Mailbox was a great app for those who really liked it, however it unfortunately is entering its end of life. Maybe someone will pick it up, but lets not count on that. Instead, we’re searching for alternatives. One might be Mail, with some addons.
Mail, by default, works well will Google, has swipe actions, and is a great desktop app. However, it lacks snoozing which is one of those things Mailbox users really liked. The good news is you can grab MailTags and add snoozing to Mail.
MailTags allows you to tickle messages which is a way to move messages out of your inbox and it’ll remind you when you need to deal with them. I don’t know why they don’t call it snoozing, but it’s similar. MailTags also gives you better integration with Gmail’s labels, ability to group emails by project, integrates with calendar, and more
If you need even more control, you can also get Mail Act-On which gives you custom workflows.
I’m not sure that there is a great replacement for Mailbox, but Mail with a few addons might get you close.