I have one, but I feel pretty burned by them since the model I bought was immediately outdated because the next hardware version after mine was a new cpu arcitechure, and the new software updates don't support the old architecture. I think they moved from arm to x86 or something like that. So I'm stuck with old software that's no longer supported, only a year or two after I bought the up to date model.

And, yeah, as the other commenter noted, it does feel quite like you're using knock-off software. Remoting into it doesn't really fill me with confidence. Maybe it's fine but it just looks/feels like the cheap and shitty version of something more reputable. And it's not even running a proper version of linux that I could customise - it's a stripped down version of arch that I can't install anything on unless it's on their official app store, which doens't even work half the time, and when I do install the official version of plex/etc the cpu is so wimpy that it can't even direct stream untranscoded video directly off the disk. My raspberrypi 5 is literally 10x (!!) faster than it in cpu benchmarks. You're probably right that I could probably overwrite the os with something better, but then what's the point in buying an expensive NAS when you could just buy a pi with much more power, community support, packages, etc, plus a dumb external usb enclosure for half the cost? Maybe the more recent ones with the updated cpu architecture are more powerful and have better apps, idk, but now I just use it as a dumb hard drive enclosure and do any smarts, such as plex or scripts I need to run, on my pi anyway.

So, I'm considering just moving all my NAS/plex data to an external drive attached to my pi.