I wanted to share my experience with the KBDFans EC Stealth Extended 2048 Biip keycap set in case it helps any potential buyers with their decision to buy these.

Firstly, I love the aesthetic. That's what made me buy these in the first place. I have always really liked biip's retro inspired legends.

However, I would not buy these again. I tried really hard to love them. I used them for a collective 6 months on my RF R2 and HHKB Type-S. Every time I roll this set, right around the 2-3 month mark, I break and switch back to the stock keycaps. Why? Because the KBDFans set is audibly pitchier, pingier, and hollower sounding. When you do a side-by-side comparison, it's quite difficult to pick up on the differences between stock and KBDFans, especially on the 1U keys. But when you use them for an extended duration of time, you pick up on the pings and subtleties that slowly drive you crazy. Switching back to stock is always immediate sweet relief. The KBDFans space bar is particularly egregious. I could see maybe using the 1U keys if you really love the aesthetic, but I would not recommend using any of the stabilizer keys.

Not that this matters much, but I've also noticed that the KBDFans set pop on and pop off with extreme ease whereas the stock keycaps are really stiff when you install them; you have to really push down for them to click into position. It's minor, but the stock keycaps feel much firmer. I suspect that the KBDFans set is thinner/uses less plastic, which would also explain the pitchier sound profile.

FWIW, I have read numerous similar complaints about the white HiPro set that released a few months ago. For these reasons, I will not be buying KBDFans EC sets again unless the quality significantly improves.

TL;DR If you care at all about sound profile (which I reckon most people using Topre boards do), then you should not buy this set. If aesthetic is your primary concern, then knock yourself out.