I rented the Panasonic/Lumix 7-14mm for a week on a trip to the mountains this past October mounted on an EP3. I found it had really nice optics but with a few hiccups. If you're shooting towards the sun, it flares. It also has a great tendancy for CA (pruple fringing). Otherwise, it is a fun lens to have.
I did not have to use an adapter, direct mounted.
Barrel distortion can be quite prominent at 7mm and close to the subject.
With the sun behind you, the colors and contrast are very acceptable.