The fan boys of the latest and most prestigious will eventually chime in and say something along the line of: NEUMANN! Hands down. But I've found it's not so simple.
It will entirely come down to what you like to use in your space. And the only way you'll know that will be through direct auditioning in your space. That being said, the KH120 is said to be an excellent little monitor. I have read and heard enough about them to accept that possibility as realistic.
I have personally used the VXT4 for a few years now, and I maintain the position that it is an excellent small monitor for mixing and tracking, one that performs much better than it's price might suggest. You can't judge it's quality based on price or hype. Just get them in your room and make your own decisions.
yeah, I ordered the VXT4 today. The idea is to have these in a second room, where I have a second laptop and NI maschine. So I thought the Neumanns might be a long-term decision but after all they are only 5 inch speakers. Then I rather spend less money on the VXT 4 and might get the 310 one day (replacing my mains).
I auditioned the VXT4 some time ago in a shop and was really surprised.
Never heard the krk's you mentioned but have the 120's and my mixes are translating well. In the end it's all preference and price tags so the real decision is up to you! Best advice would be to listen to both then decide if possible.