I use voice dictation quite a bit and I haven't really noticed a difference between Siri and Google Assistant with respect to accuracy. I'm not generally in noisy environments though.
I'm very much a software-first person. I bought the iPad to run GoodNotes. It's the only good note taking device I've ever owned. Since then I found Procreate and use it all the time as well. It's an amazing program.
My phone is used mostly for voice calls, text messages, maps, and listening to podcasts. I want to run Things and Overcast on my phone and that's my primary motivation for moving to iOS.
As far as notification go, I generally disable them. I want to know when I get a text message and that's about it.
Long story short, I returned my iphone 13 pro. I found that, for me, the way I use the ipad and the way I use my phone are completely different. On the ipad I use it almost exclusively to consume content. Websites, youtube, streaming, email (but only using the browser). I found that I use my phone more as a “mobile command station” for my life. I get notifications and react to something, or I use it to launch an app to do something (like my blink camera or thermostat). I constantly scan it for notifications and do something with those. I rarely spend time watching videos or consuming long-form text.
And for those things, at least for me, ios just pales in comparison to Android. Android notifications are just so much better. I can scan them and act from them better than I can on ios.
Lastly (and the straw that broke the camels back), voice dictation on ios is laughably bad compared to Android. I was just becoming annoyed that android seemed to be missing more and more words for me lately, but when I tried to use ios dictation in anything but a perfectly quiet environment it is unusable. I use this a lot, so it was a deal breaker for me.
Quick anecdote, I went to a concert recently before I got my iphone and texted my wife while the canned music was playing before the concert started. It was not as loud as the band, but pretty loud none-the-less. I used voice dictation and just after I did it and scanned it for accuracy, my iphone-using friend said under his breath “that aint gonna work!” right as I hit the send button. I remember him being mildly surprised when I hit send, but didn’t think much of it until a week later when I got my iphone and tried to use it out in the wild in a similar way. I then reflected on that and understood his perspective.