Not sure if I'd pick OIDN over Cycles with those artifacts at very low sample counts, but I honestly just wouldn't pick ANY of them below the 64 samples version, and above that point OIDN clearly the best job by far in my eyes.
I think denoising should be something that cleans up the last trivial remnants of noise that would take ages to get rid of with raytracing, not something that lets you get away with broken renders in the first place. That might change with future developments, but for now I'd rather just sacrifice lighting and material complexity for less noise, rather than live with either artifacts or splotchy smeary noise.