dawkinscm wrote:As I said before, machine generated scores doesn't guarantee the best looking picture because human perception and preference isn't objective. The other thing I said is that much of this is designed specifically for Anime and that definitely applies to ArtCNN. So hopefully you are an Anime watcher 
Also don't forget there are different levels to it, for example I would never use strongest FSRCNNX because it would introduce too much sharpness for non-Anime. However, the one I do use, is always very helpful in improving the sharpness just a little a bit because I have the TV sharpness set to 0 on the LG C2.
TV sharpness is much worse than these AI shaders btw, so actually using the shaders as an alternative and toning down the TV ones definitely helps.
In most cases though, I imagine people here use monitors, which automatically have sharpness set to 0.
It also wouldn't make sense to use these upscalers on a 27" or 32" 4K monitor, as again like @dawkinscm says, it would look too sharp.
However, watching on a 42" screen, and I have been using 42" and 43" screens for almost a decade now, I started using FSRCNNX in its very early days and have not looked back, it is great.
So, a lot of factors play a role, no harm in testing and seeing what you prefer.
For reference, I use FSRCNNX_x2_8-0-4-1.glsl, which is the 8- and it's very low sharpness compared to the 16- and 32-.