Panasonic 7-14 f4 or Olympus 12mm f2

I'm new to µ43, having found that I'm no longer as game as I once was for carrying around my heavier Canon gear in as many circumstances as I would have several years ago. I've been shooting mostly with a Ricoh GRD IV for the past several months and have been quite pleased with some of he results. However, more versatility and weather sealing have led me pre-order an Olympus OMD/EM-5.

For landscapes, I've normally shot at about 100mm EFOV, 45 EFOV, and 20EFOV. I'll get an Olympus 45mm f1.8 for the 100mm role and have a few legacy glass candidates for the 45. However, I'm a bit torn about wide lenses. In terms of image quality, say at f4 or f5.6, how does the Panasonic f4 7-14 compare to the Olympus 12mm F2? To make things even, are there significant differences in their characteristics when the panasonic is used 10mm or 12mm- contrast, flare, colours, etc?

Thank you in advance for any replies. I've put in a few photos that I had a chance to take in situations where I certainly wouldn't have brought a large camera.