What kind of ssd are\were you using? High performance?
Good points indeed.
But my take here is that we can have "3" main issues so far:
1 - Your x86 router\mini pc can come with an ES CPU
2 - Thermals
3 - Cheap and possibly inefficient and\or unreliable Power Supply
The first one is a big one! What i mean by that, is that getting an ES CPU while expecting to receive a retail one is a really bad thing since its not stated anywhere on the sales page that is an ES CPU, so the router\minipc should be returned without a question... In other words, its a situation that the person who bought can't easily fix it or work on it by themselves.
The second one can be worked on using several ways, so to me it can be fixed with some DiY if needed! Which is something that does not seem to be the case for everyone(by the reports on this thread), because not everyone is trying to use high performance NVME SSD's and such, in a passive cooled system and we know for a fact that high performance NVME SSD's will generate a lot of heat.
The third one can also be fixed easily by buying a good Power Supply.
I don't know how is it for you guys in the countries where you live? But here where i live(Brazil), i can buy these systems and pay only the price being charged on Aliexpress, in other words, in my country there is a really high chance that it will pass customs and it will be free of import taxes! So paying 200 bucks with free shipping for a V3 system is really cheap
So for me, the specs + the really cheap price + the ability of DiY to fixe some, if not all of the "possible" issues = pros outweigh the bad.
Also lets keep in mind that the thermals issue happens even with respectable and specialized manufactures! As for an example, i had thermal issues with an Asus RT-AC86U which i used from 2017 to 2020 as my home network router with asus-merlin and a lot of community scripts installed... My Asus had terrible thermals, with the cpu running always above 70°C(i was having thermal throttling issues in summer, which made my buy some fans for it) which was a common complain from every owner of that model and more recently, i saw reports of ppl complaining about the RB5009 from mikrotik being "too" hot.