I like the promise of iPadOS 13 (the rebranding of iOS for iPad), but I can't say I'm very pleased with the iPadOS 13.1.2 implementation. It appears the designers have been fixated on users with the large-screen version of the iPad Pro - on the normal size screen the interface is now cluttered and occasionally I have to move the keypad out of the way when previously I didn't. However, that said, the full keypad can now be pinched down to a floating phone-sized keypad occupying less screen area. The home screen icon size & layout can be restored to "normal" (for 10" users) in settings.
People might like the new facility to choose their home screen background, but I have never been a fan of that (even on desktop operating systems). For me, that should be reserved for screensavers, but if you like your workspace icons camouflaged by a busy distracting background of your latest holiday photo, go ahead (on the desktop, I use different plain-colour backgrounds to differentiate between user and admin logins). There's no harm in offering choice, but I wonder why they've decided to play catch-up with something that practically every other operating system has offered since Windows 3.1, after all this time without it?
There are some goodies: the major one so far as I am concerned is that any (updated) app running in iPadOS should now be able to access files on external USB (and NAS I think) drives without using a third-party app to import them first (for which I was using FileExplorer). I have used a cheap Chinese Lightning to USB/SD adapter and browsed a micro-SD card (in an SD adapter) for video files recorded by a GoPro knock-off using Files - and they play!
Highlights (promised, but not all yet explored):
External file access (mentioned above)
Screen "Dark Mode" (switch to essentially white-on-black instead of always black-on-white)
Configurable notification area now available directly on the first home screen, with widgets
Extended multitasking with app slide-over (not available on all models)
Font manager & installable fonts
Zip/unzip available through the OS
Safari requests desktop site by default
Download manager in Safari
Attachments to calendar entries
Multiple instantiations of the same app
Direct access to WiFi settings etc by long press from the Control Centre
"3D" touch actions (time, not pressure) for dock icons etc
Shortcuts macros available as home screen icons (and dock)
Dock icons groupable (may have been possible before - didn't notice)
Video editing in Photos supports crop and brightness/contrast/colour adjustment
Taking screen shots in Safari offers the option to use the whole web page instead of just the screen when opened for editing
Typically, the new features make some third-party apps redundant. But these things come at a price. Some bugs have been introduced (which might get fixed), and other features downgraded:
Switching away from and returning to Safari doesn't always preserve the current zoom (even if it was 100%), even if done by home button actions and not swiping.
The reply button when reading an email has moved (just needs getting used to).
The Dolphin browser app is broken (crashes on start-up).
Video clip editing in the Photos app no longer offers to "save as new clip" (but it does in Files).
"Insert Photo or Video" context menu option in Mail now opens an image selection pane without a "use" button, just an "X" - selecting a photo inserts it in the email immediately, but if it's a video that takes so long (while the video compresses) there's no feedback. All inserted images are shown selected, so you can't insert the same image twice even if you want to (with that particular method). (To insert a photo, click the camera button and you get the proper selection pane with a "use" button again.)
The "Reply" hover action over selected text in a Hummy.tv forum post doesn't work (strangely, "Quote" does work).
Auto-correct text (in composing forum posts) is even more mental than it was before.
I like Shortcuts (essentially a macro facility), but why does it rely on having Siri enabled to do anything really useful, when it doesn't need voice recognition for the facility in question (eg: turn Bluetooth off properly)? Work-around: enable Siri (ugh!), but set it to only activate on a long press of the home button.
for people who are interested in running iOS 13 Apps with no issues — A — Accuweather Activity++ ADT Pulse Affinity Desktop Affinity Photo Airbnb Air Canada Air miles Alarm.com AliExpress Altimeter+ Amazon Amazon Alexa AMC Theatres Amex AnyConnect AnyList ANZ Apollo Argenta (Belgian bank)...
Discovered another highlight: taking a screen grab while viewing a web page, and opening the screen grab for editing, gives you the option to use the whole web page instead of just the part on screen. Nice.