Get GH4 with Olympus 12-40 OR Panasonic 12-35?

I sold my Panny 14mm & 20mm primes as I really didn't care for those lenses. I really want to buy at least one decent native M/43 zoom lens. I would really appreciate some advice in regards to the pro's and con's of each lens on the GH4. So those of you that have the GH4 with either lens please chime in with your thoughts.

I am leaning towards the Olympus due to the build quality and manual focus mechanism but want to make sure I have all the facts first before purchasing this lens.

I have some questions for those that may have both lenses.

Olympus lens questions:

1. When shooting stills and video on the GH4 with the Olympus 12-40 lens does the GH4 correct for distortion, chromatic aberration, etc.
2. Is there a major difference in color rendition from the Olympus 12-40 compared to Panasonic lenses?
3. How does the manual focus feel on the Olympus in comparison to the Panasonic?

Panasonic lens questions:

1. When shooting video on the GH4 with the Panasonic 12-35 does the GH4 correct for distortion, chromatic aberration, etc.
2. Is there a significant difference in focus speed in comparison to the Olympus 12-40?

Thanks in advance for any help.