Let's get one thing out of the way first. You can absolutely get some work done on any of these tablets. (I'm currently writing this review on the Tab S9 Ultra.) The recent improvements in Android for tablets have made it easier to use two apps side by side in split-screen mode, and Samsung lets you have a third app as a floating window in between them. You can collapse this app into a floating bubble or move it to the edge of the screen until you need it again. (This is great for messaging or music streaming apps.) You can even have two Chrome tabs up and running side by side.
Even better, I'm currently using Samsung's DeX with a Bluetooth keyboard. This is a mode available on Galaxy mobile devices that enables a more desktop-like interface, with a taskbar at the bottom and resizable app windows that resemble the experience on a Windows or macOS machine. You can also connect the Tab S9 series wirelessly as a second screen with Windows PCs, or pair the tablet with an external monitor via a cable for a dual-screen experience.
However, none of this functionality is free of quirks. When paired with a portable monitor, I noticed that the monitor enters DeX mode, but the main tablet screen retains the normal Android interface. I'm not able to use my mouse to move the cursor from the monitor back to the tablet's screen—it just stays on the portable monitor's screen, and I can only control the tablet's screen with my fingers. Everything feels disconnected. (Update: After troubleshooting with Samsung, it looks like you can move the cursor between tablet and monitor—you have to access DeX's settings on the portable monitor first and head to the mouse and trackpad section to have the cursor flow from one screen to the other.)
I also hate that opening a new Chrome tab doesn't automatically put the cursor in the URL search bar, so I always have to manually tap there before I start typing. And sometimes, my Chrome tab refreshes when I come back to it after using another app, which can mean potentially losing any work that's not saved on that page. I've also noticed that some apps (like Telegram) don't show their multipane design in DeX mode, despite it being available in the normal Android tablet mode.
I've run into more issues like this, and they do end up having an impact on the overall experience of using the Tab S9 series as a computer replacement. So while I got work done, I still needed my desktop machine to get work done fast. That said, I still enjoy the flexibility of turning off DeX and using these Tabs as normal, fun tablets.
Sharp Hardware
The 120-Hz AMOLED screens on the Tab S9 series are wonderfully colorful, bright, and sharp. I just wish Samsung would add an always-on display mode to make the screen more useful when in standby mode. Instead, you just get a blank void until you tap the screen. The quad speakers push out an impressive amount of audio, though I found some songs sounded a bit flat compared to how they sound on the iPad Pro. Battery life, thankfully, has been pretty great all around. I worked for six hours straight on the Ultra while plugged into a portable monitor, and it only dipped to 40 percent.
There's a microSD card slot in case you want to add more space, and each Tab S9 comes with an IP68-rated S Pen stylus. (The tablets are also IP68-rated for the first time ever.) I quite like using the stylus to write down my tasks in apps like Goodnotes (which comes free for one year) and Samsung Notes, and it worked well for drawing, though I don't sketch as much as I used to.