Well, I have no regrets. I bought the black RF 87U, and a white RF 87U. I also got pink lettered caps, pink blanks, green lettered, blue lettered, red lettered and white lettered. I also have a white HHKB Pro 2 Type-S with blanks and lettered keycaps. Why am I telling you this? To brag? Hells noe. Only a fool would brag of spending money. The wise man buys stocks and bonds. The fool buys keyboards. But I digress. What I'm trying to say is that I've tried them all, and I can tell you that IMO the best are blanks.
After much reflection, I currently think white blanks with grey modifiers is my favorite color combo. Second best is black blanks (which I don't actually have right now). Third is the black on Charcoal. I still like pink with either letters or blanks, and the green lettered. I've sold off the rest. I dunno if this helps or not.
Here is my current daily driver:
