I lubed with EK-mechlube 2. I've been told that I should not use it to lube the HHKB here on geekhack, however on reddit I heard otherwise. Alot of people used it to lube their HHKB's on reddit and came away happy, so I decided to just do it because it was killing me inside.... I had to know what my 55g HHKB felt like lubed.
While in my opinion it didnt make the keyboard worse, it just made it different.
Pre-lube the HHKB to me personally had great aural and tactile feedback. So much thock.
After lubing, it kind those two things kind of got lessened. Its still there, it just went from a 9/10 to like a 7/10.
On the flip side, lubing it absolutely made the keypresses smoother. Although, in hindsight the keypresses pre-lube were already smooth.
So yeah basically, it took away the thock and tactility that I crave for.
Edit : Oh and I only lubed the switch sliders, nothing else.