The only one with priority inbox and fully integrated mail and calendar. Not perfect, especially working with Google Workspace, though the annoyances are less than anything else I have used.
Unusable. No notes? What were they thinking of? The sync on the old version is rubbish, the new version is fine, but I cannot migrate as I need the native Notes, so I am stuck with a poorly performing sync process, but at least I have all my notes. No news as to when they will be reinstated, nor explanation as to why they were excluded.
I'm not an Outlook fan. My company has to use it for its security because we work with a lot of enterprises, but I'd switch back to Gmail in a heartbeat if it were up to me.