Brightness and contrast
The ASUS Designo MX34VQ has a decent, but not extremely high maximum brightness of 275 cd/m². Sufficient in most circumstances, but if the imaginary CEO of two pages back is in a corner office with light from every angle it might not be enough. In any case, it is more than enough for regular indoor use. The Dell scores a lot lower in comparison, but if you read its review you know why: standard, the U3417W has uniformity compensation turned on – this results in better looking, more even lighting, but also reduced brightness and contrast.
If you also want to sit behind your desk in the dark, you want a low minimum brightness. The ASUS performs solid here with a value of 37 nits. Slightly more than the Dell, but not blindingly bright.
The black value is of huge importance for the contrast and usually a strong point of va-technology. Indeed, the MX34VQ does not perform bad at all, with a value of 0.07 cd/m² at a brightness of 150 cd/m² and 0.14 cd/m² at maximum brightness. We have seen even darker va-panels in the past, but this is clearly better than any ips-monitor you could think of.
The excellent black value shows its added value with the contrast, which is excellent however we measure it. The difference with the Dell, that is handicapped by the uniformity compensation, is rather extreme, but even the best ips-monitors are not above about 1200:1.