My grey-on-white keycaps set came in yesterday, just got a chance to put them one this morning.
You can see my first mech keyboard there on top left (Filco "Otaku" browns) and the one I'm switching the keycaps is Filco TKL blues:
For those that might be interested, here's the link to group buy thread. The shipping was fast considered it came all the way from HK (took around 5 - 6 business days via DHL). One of the boxes was a little beat up but the keycaps inside were ok.
The quality of the keycaps themselves are top notch. Highly recommended if you're tired of the same all black look or your keys are getting shiny.