I never considered the superzooms (now both Panasonic & Olympus have µ4/3 versions) because of the serious compromise in IQ. This lens really seems to tilt the scale toward the IQ side (at the cost of higher price and bigger size/weight).
Here's my question (to soundimageplus or anyone else with this lens): How well does it handle on the G cameras? I wouldn't expect to hold the lens by the camera grip alone, but is the grip enough to help orient the camera-lens combination? Is there enough fixed space on the lens (vs focus / zoom / aperture rings) far enough away from the camera body to let you stabilize the camera while shooting?
In the olden days, I would have walked into Palmer's (in Berkeley) or Brooks (in SF) with my G2 and tried it out myself. These days, you never really see a lens live (especially an exotic like this one) until UPS or USPS drops it off.
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.