I currently have a Samsung Galaxy Tab S2 [SM-T819Y]
Me too. My only real complaint is the poor accessibility of the quick settings tray (where you do things like frob the WiFi on and off). For reasons best known to Samsung, they've changed the perfectly clear default Android colours to pale blue/grey on white, with the result that you can only tell if a given setting is on or off by cranking the brightness up to full. This hasn't quite built up enough inertia to make me install an alternative firmware, but only because I'm lazy.
I find the whole Android eco-system much more user friendly and functional for my usages including touring, riding up my daily ride notes etc.
Touring was the main reason I got such a high-end tablet: I wanted something that had a real filesystem so I could transfer data to and from my eTrex and potentially a camera, which meant Android rather than IOS. I wanted to use it as a substitute for paper maps, so SD card storage was almost essential and GPS was highly desirable. I wanted cellular connectivity so I wouldn't have to drain the battery on my phone to connect it to the internet, and so I could hedge my bets with two different service providers.
I have the posh keyboard/case for it, because the rest of the time it gets used as a mobile SSH and IRC device, for wrangling of servers and talking to barakta. I tried a cheaper keyboard and sent it back because the case was shoddily made and meant portrait mode (which I use extensively for reading in bed) was impractical.