Okay after a first try on my crappy laptopspeakers I listened to the files in the studio.
First of all the levels had to be matched, as the difference is around 2,5 db !!!
Second, the variable-GM is much more compressed than the ES-8, so no real comparison possible.
But in the studio I didn't really like the ES-8 as it darkens the music too much and sounds very squeezed.