I find it handles well. Its not unusual for certain lenses on DSLR systems to be heavier than the camera. The Vario-Elmar is somewhat larger than the Olympus superzoom though. I had a Panasonic 14-140, which is close to the same size as this, but miles away in terms of image quality.
Its not outrageously heavy, around 500g, and I'm so used to supporting a lens barrel from my DSLR days that its second nature. Its the smaller pancake lenses I don't quite know what to do with!
I would say that it handles better on a GH1 than on the Olympus Pens. I've not found the grip on the G series particularly comfortable, but using a lens like this it comes into its own, since it gives a better balance.
Know what you mean about seeing a lens in the flesh. I did lots of research on this lens before buying it as there was no way I was going to be able to try one out. I'm glad I did because it is truly wonderful. Heavier than most of the m4/3 lenses granted, but I do save on not having to take anything else out with me.