Qualitative

In English, this word is almost only ever used as the counterpart of quantitative. It doesn’t mean “high-quality”.

Relating to the quality rather than the quantity, particularly in research looking at the general nature rather than backed up by numbers. As well as that more technical meaning, though, the Dutch equivalent, kwalitatief, tends to get used simply to mean “high-quality”.

• kwalitatieve websitecontent => high-quality (not qualitative)
• kwalitatieve producten => high-quality (not qualitative)
• kwalitatieve woningen tegen betaalbare prijzen (the example used on taaladvies.net)

(Note, by the way, that high-quality when used as an adjective needs to be hyphenated.)

Prevalence: moderate. As the counterpart to kwantitatief, Dutch authors – researchers and so forth – largely use the word correctly.
Frequency: low. It’s the everyday use that goes wrong.
Native: no. Other than in contrast to quantitative.