I have owned every iPad mini ever made. The iPad mini 5 was a noticeable step up in speed over the 4, which was a noticeable step up from its predecessor; but I can’t say that the mini 6 is any faster than 5 simply because my mini 5 was not slowing down over time. If there was no iPad mini 6, I would still be happy with my iPad mini five other than the screen not being bright enough to use outdoors to my satisfaction - it was marginal.
Pros: Where I see the biggest improvements are (1) the ability to hold it in portrait mode without a case and not covering the screen, because the square edges make it easier to grip (my case arrived a day late), (2) the speakers on either side of the screen are great when I’m in landscape mode watching movies, (3) the bigger screen is a nice bonus, and (4) the new screen is blindingly bright indoors, and much easier to read outdoors - I was pretty much using a Amazon Kindle for reading books outside, until now. (5) I can run more apps at the same time now, without having them get pushed out of memory and reloading after I switch apps, and this has been a big plus. (6) My Wi-Fi speeds have more than doubled, as we have an Asus Wi-Fi 6 GT-11000AX home network with two AX92U AI mesh network nodes - I went from 142 mbps to 525 mbps on Wi-Fi (wired iMac sees 940 mbps). (Have not tested 5G yet, But I have been perfectly fine with 4G/LTE and may end up turning off 5G if it improves battery life even more).
Cons: Where I’m having a more difficult time using this mini 6 is that when the iPad is in a case and standing up for watching movies I now have to unlock it with my left index finger instead of my right thumb, and muscle memory has me reaching for a missing home button with my right thumb ? Also not being able to use my original Apple Pencil was a bit costly. I liked the fact that I could use a female to female lightning connector to charge my Apple Pencil 1 without the iPad, but at least Apple Pencil 2 does not take up the only port on the iPad mini 6 that would be used to charge the iPad itself. I’m happy I can charge both at the same time with one cable. I do not like that I have to use a bulky dock or 3rd party cable in order to use headphones and charge at the same time, and think this should’ve had wireless charging.
I always hand down my old iPads to my son, and he is much happier with my old mini 5 than his mini 4. He said that with his iPad mini 4 that his battery life was horrible, and it was experiencing long delays between commands and responses and load times. After migrating him to the old mini 5 I did witness his mini 4 battery drop from 100% to 15% over 22 hours, while just sitting untouched in standby on Wi-Fi, with background app refresh turned off (no SIM card, no apps running).
Battery info did not show anything running in the background to drain the mini 4 battery, and he was not making changes to his iCloud account on his iPhone that would’ve been synced to it to drain battery. I will be interested to see how long the iPad mini 5 battery lasts after restoring his back up onto it, Since he did not do a clean install.