Plenty of people will say 4000 is perfect white light. I prefer 3000- whiter than the halogens you had but not clinical.

IMO 4000K is the perfect light it mimics daylight and keeps the yellow cast from happening. I had halogens for years and never had yellow light so not sure what you had. As for the fixtures you are getting they look like the bulbs are integrated and I would not ever do fixtures with integrated bulbs there are tones of choices where the bulbs can be replaced . No to 500 and up for the light it will feel like a warehouse .

The fixtures I am using do have lights integrated but the settings are adjustable from 2700 to 5000, I will have my workers to change it today, hopefully it will make a difference. And I agree it looks like wear house bright but with grey tone on the setting I have it now.

Good luck with the lighting project! Test out different temps & see what you are comfortable with. I prefer 3000K in homes = not too warm or cold. But like everything it depends on the effect & personal preference.

FWIW I have used the integrated wafer leds like you show in renovations where recessed housings were not possible (either for structural or insulation reasons) and like them very much so far. Have not tried them in a kitchen yet.