I’m on 800mm vibrocore bars and some well padded Odi grips. I wouldn’t be able to say yes, the vibrocore definitely makes a difference unless I took them back to a week of the alpine braking bumps that screwed up my hands a bit with cheapo ali bars last year, but the combination is noticeably plush and I’ve not felt any numbness, buzz or other effects in my hands in the months since fitting them. Placebo effect entirely possible.
I met Mike a few months back and asked him if it was just builders expanding foam. Short answer: No, they spent a lot of months experimenting with different foam types, and found the right foam in combination with internal caps not only attenuates vibration, but increases the fatigue life of the bars.
(Edit: If you do go for vibrocore bars, the 800s are made of a more complaint alloys than the 760s).