Both (Android 11/12 and iOS 15) are great operating systems. To be honest, they're almost more equal than ever before. We have gesture navigation in the same way on both systems, we have great ecosystems on both systems, we have great apps on both systems, we have much power on both systems.
For the regular user there isn't any significant difference between both systems. I think the things to bother are in detail. When it comes to special use cases the details may decide the chosen ecosystem and platform. Let me give you some examples for both platforms that aren't mentioned a lot.
Apple:
- Watch unlocks Mac (Desktop)
- Watch unlocks iPhone (e.g. waring a face mask)
- Calls and messages are forwarded to all devices (this comes handy when you're working on your Mac. For me this is often the case that I'm developing and in focus with music on AirPods, someone calls me and a shot notification appears on my Mac where I can answer or reject the call. When answering the call with a single hit on my keyboard, the music stops, and I can directly speak. No need to get out of the focus, watch for the caller on my phone, stop the music, take out my TWS, grabbing the mobile and answering the call. I love this!)
- Message forwarding on all devices with auto fill on all websites and apps for 2FA
- iCloud interaction for Photos/Videos when editing (so further importing on files needed, can directly access the media from the Library, no further manually upload/download of content)
To be honest, this are mostly features when running a full apple ecosystem including iPhone, Watch, Mac, as well as having a paid subscription of iCloud. Missing just a single thing may drop this where it comes back to the equality of both systems. If I would stick around with Linux or Windows as Desktop, most benefits would be lost.
Android:
- Independence of system upgrades (I like the method that core/system spaces can be updated without upgrading the whole OS. This comes very handy when you need to patch single things quickly where it can be delivered via the PlayStore instead of a whole firmware update)
- Easy sideload possibilities (that's the correct way)
- Things like DEX (I love Samsung DEX which makes a Fold to a mobile phone, tablet and a whole Desktop. In the past, I used this feature a lot.)
- Diversity of hardware (you are not limited to a single device, you can choose between so many devices that fits your needs in price, quality, hardware specs etc.)
- TBD: Finally working upcoming syncs between Android and ChromeOS (and Windows/Linux) to enable features like answering the call directly on my Desktop. Forwarding text messages (mostly for 2FA logins). Yes, there are workarounds to get this - and yes, they're workarounds.
Back to my opening paragraph, I think both systems are more qual than ever before for the most and it only becomes relevant when you need full integration of all features which is more or less depending other devices you use.