I was all set to purchase a Lexus GX 470 after seeing one at an autoshow, which would have replaced my Sequoia.
However, after doing further research on this vibration thing, I have changed my mind.
Several posts in this and other forums have noted that Lexus has admitted to this problem, and is currently looking for a fix.
Now that Lexus has admitted to it, there really must be a problem here, and that has convinced me that spending $$$ for this would be a mistake.
I hope if anyone hears that there is finally a fix for this problem, they will post it here.