NVIDIA Jetson Xavier is quite usable as a "workstation" as well. I actually develop ARM SIMD code on it. 8 cores + GPU. $700 on Amazon right now.
As a word of note, though, the chips in the Tegra machines are, IME, extremely powerful -- but you're stuck with Linux 4 Tegra and Nvidia's Ubuntu-based distro. At least for the TX1 there was some success getting other distros working (without GPU) but I remember several people running into trouble with the TX2. That may or may not be a dealbreaker for some people (it's a sort of franken-Ubuntu and your only hope for problems are the Nvidia forums)
The Solid Run LX2K machine however should (eventually) run any standard AArch64 distro. They also have 16 cores and expandable SATA, as well as an open PCIe 4x slot on these boards, so you can install whatever GPU you like onto it. Not to mention you can plug in a bunch of RAM. You can even buy a slightly different variant of this board with a 100GigE cage on it, still under $1000 USD, which puts it in a very unique position vs any other I've seen.
I think the LX2K boards are (now, at this point in time!) a much better sell if you want an actual "arm workstation" as a developer. But the Xavier will be vastly superior if you want a lower power profile (mobile) or if you're doing something like DL inference.
As for Xavier it is a good platform, but you in many benchmarks the HoneyComb LX2K is way out in front. Then adding in the 10Gbps networking and storage.
Also, Franken-Ubuntu I suppose isn't really my complaint, though I still don't like it. It goes beyond that, though -- the Tegra boards have very custom design that means some things are a huge pain in the ass if you want to even remotely treat them like "normal" computers (for example, want to test that fancy driver you wrote on your AArch64 Tegra machine for that M.2 peripherial? well first you gotta reconfigure the BSP firmware to turn off the power rails to various subcomponents so you can reroute them to things like the M.2 E key slots in the TX2. Gotta disable that USB controller via BSP flash if you want a chip in there, etc etc). It also means I am basically stuck on older kernel versions which may mean features I want to use or develop with are basically off limits (eBPF enhancements, io_uring, etc.) I don't just want to test SIMD; I also need to test actual memory/disk/peripherials, etc. These constraints make perfect sense for Tegra devices -- they are still annoying, for me.
I'm not saying the Tegra machines are not nice, or they are not high quality. They absolutely are. If you are just writing code to give the CPUs some work to do, they are great! Flash the default BSP, plug in HDMI, run 'gcc'. They're the highest performing ARM machines for their power profile and size, IME. But the moment you treat them like an "ordinary" computer, all bets are off. These LX2K machines act substantially more like "ordinary" desktop computers, and IMO that's a significant benefit.
Now, if you want to do DL inference or GPU programming, I think CUDA is vastly better (for a number of technical reasons). And the Tegra machines would be a good choice! But if you're just writing ARM code and need a desktop, these machines seem perfectly sufficient and can host open source drivers just fine, and will be far more usable in a number of ways vs a Tegra machine.
(And also: Nvidia also released some press notes last month that they would be bringing the full CUDA stack to ARM for data-center computing, presumably, including the host driver. So it's possible you may be able to stick a Quadro into these things soon enough and use CUDA to your hearts content!)
That I do agree with. I wanted to buy an ARM machine to do CI for one of my clients, and currently the only real option for that seems to be Cavium ThunderX. And pricing is way out there in the stratosphere for what you get. Instead I could see them deploying a few of these for a fraction of the cost.
Also 99.999% of people want to "use" software, very often proprietary one, not re-invent the wheel. No matter what, this kind of product will be a niche, by an overwhelmingly large margin.