I've bounced around Google, Microsoft, and Fastmail for the last 4-5 years trying to find a sort of "holy grail" solution but I've learned there really isn't one. Google comes closest (for me personally), but the privacy implications and vendor lock-in always end up scaring me away.
Fastmail has really outstanding mail support, but their calendar service definitely leaves a lot to be desired (i.e. if you want to share a calendar with a spouse with any sort of authentication, spouse needs an account too), and their file support is minimal.
I think the answer is diversification and make sure you're a paying customer for whatever service you use. Use your own domain, spread your data around, use standard formats (text, etc.), and keep backups. Otherwise, you're just asking for trouble.
Fastmail has really outstanding mail support, but their calendar service definitely leaves a lot to be desired (i.e. if you want to share a calendar with a spouse with any sort of authentication, spouse needs an account too), and their file support is minimal.
I think the answer is diversification and make sure you're a paying customer for whatever service you use. Use your own domain, spread your data around, use standard formats (text, etc.), and keep backups. Otherwise, you're just asking for trouble.