There is a trade off between availability (spread it around) and privacy/confidentiality (the more places it is spread the more you are exposed to risks of hacking or insiders at any of the companies). There is no right answer but it depends on the person and the content.
I think you greatly reduce your risk by spreading it around. There cases where people have had a single Google or Apple account compromised and lost everything. That wouldn't have happened if their stuff had been distributed... though you'd still be in trouble with an email account hack, because of password resets and passwords sent in plain text emails.
There's also a tradeoff between availability and the fact that many of Google services are simply an order of magnitude better (both in terms of functionality and user experience) than anything else out there. I happily use DropBox instead of GDrive for syncing files, but I'm yet to see an acceptable replacement for GMail.
