Months ago I was like "if it's more than 600€ it will fail" ... and the argument "it's the medium hardware of steam users" didn't helped in a better direction ...
At the time, the only thing that could have made "that new pc" worth something was the price. (That was also one of the reasons why the Steam Deck sold so much, but that was also a portable device, not a desktop PC)
Now that I have seen some reviews I'm actually pretty mixed ...
it's not cheap and not a very powerful machine, but it is already way better than my 10 years old PC ... (my graphic card has 2 GB dedicated RAM versus 8 of the Steam Machine ...)
it's also able to run a lot of games that require Win 10+ , that I can't run with Win 8.1 ...
it uses the Steam DB to have the games already configured correctly ... this is a really cool thing ... I use a lot of time to find the best compilation of settings for every game in my machine, and the more recent are the more I have to play with the settings ...
In all the reviews I have seen they gave compliments for the form factor of the hardware ... the fan is huge but with low noise, the antennas are placed in good spots, dedicated connection for the Steam controller, etc ...
I never got the Steam Deck just because I already have a Pandora and a Pyra as portable devices, and I have always difficulty to dedicate the time to those, but I have seen it and I know how well made it is, and if the same effort was put in the Steam Machine, well ... I start to think it could possibly become my next PC ... (at least for gaming)