I've done this exact A - B. For me, the Dynaudios won on most material, although I was impressed by the firmness of the bass on the KRKs. The mids and high-mids were definitely cleaner on the Dynaudios, and the top end feels like an extension of the high-mid quality. On the KRKs, it was as though the main driver and the tweeter had distinct characters - not unpleasant, but just a bit less integrated.

Someone once said the KRKs have an "American" sound and the Dynaudios a "European" sound. While not being as geographical about them as that, there is a real character difference.

You need to audition them both with your choice of source material. You may need to take along a CD player or hard-disc recorder that is up to the job as well, as these are both superb and unforgiving monitors.