ActionTiles keeps anonymous hardware / OS statistics of our users, and the top brands in order are:
- Samsung (trails far behind in popularity, based on the ActionTiles user sample set).
BTW: Most tablets running ActionTiles use 8" or 7" screens. People are thrifty, and 8" is really plenty of space if you tailor your Panels to the area of the home you are operating in). 8" is also less obtrusive on your wall.
So you have narrowed down to the most popular list, though don’t rule out any “decent” alternatives. I advocating buying used, though is harder to find 3 or 4 of the exact same, so this is not the best option for your situation.
Based on your specific models:
Amazon: Best hardware/price ratio by far (especially when Amazon has a sale, or check out the refurb-warehouse deals). Built in Alexa and Alexa Show Mode. ActionTiles is in the Amazon Appstore. Several inexpensive 3D-printed mounting options, and lots of users to give you ideas for mounting. Kiosk-mode browsers offer wake-on-front-camera motion detection (also works on Samsung, but not Apple). Tons of Android Apps, including Tasker and AutomateIT for macros. Links to Alexa as a display for nearby Echos.
Apple: Highest performance. Home Kit / Siri compatible (there’s an unofficial Home Kit bridge for SmartThings - don’t know if it is good). Lots of high-end mounts available. Runs ActionTiles quite well in Safari (performance isn’t great on older iPads).
Samsung: Great middle-ground for price. Native Samsung experience implies you might get the “best” possible SmartThings App experience. Samsung features (S-Pen model, etc.), are quite nice, but may not really be needed for a mounted tablet. Least “locked-down” of your 3 choices. Probably can be rooted (Search XDA forums).
Amazon: Locked down, with minimal hacking options. No Google Play Store without hacking, so harder to find some Apps. Impossible (or nearly?) to run SmartThings App - but you don’t need SmartThings App on a “daily basis”, so ActionTiles may suffice. Must remain plugged in if you want to avoid the lock screen (i.e., swipe to view ActionTiles or access anything) - but remaining plugged in is absolutely feasible.
Apple: Expensive. Rather locked down. Fewer Kiosk Mode features - I doubt there is a wake-on-front-camera motion detection option; perhaps can tap once to open? App selection is different than Android - personally I think Android has much more choice, and choice is good and keeps Apps cheaper).
Samsung: Ummm… it’s just less popular. Probably because of pretty high cost without giving you proportionate advantages over Amazon. If the SmartThings App is critical, then Amazon is ruled out though. Perhaps 1 of your 4 Tablets should be a Samsung and be your “SmartThings control / configure” master-station.
I hope the above jumble helps a bit.
Personally, in your situation, if my budget were wide open, I’d go Samsung (since I’m not an Apple fan at all). If you have any budget concerns, using Amazon minimizes your investment - i.e., less “sunk-cost” if you decide to switch 1 or all to something else.
My household has all 3, since we use them for various purposes, and yes… ActionTiles testing.