300 MM Resolution:
The first set of shots (the power pole) are 100% center crops of test shots with the DO lens at 300 mm. Not bad results, and a little better than I had expected. It's not going to outresolve the 300 f/4 L lens, but that wasn't expected either. The original image is first to help illustrate the scale of the 100% crops.

The power pole shots are all 100% crops, center image, with a small amount of unsharp mask applied.

Flare:
Added some images to illustrate flare (probably this lenses' weak point). Angles between the sun and the center line of the lens are estimated, and are not precise. The 30 degree image shows no ill effects from flare. Even the 20 degree image shows minimal loss of contrast. Considering the dynamic range of the image, that is not unexpected.

However, the image taken with the sun at about 10 degrees off the center line shows considerable veiling flare, and renders the resulting image quite useless. This image was shot with the sun just outside the frame, but still apparently hitting part of the front glass (outside the coverage of the hood). Care should be taken to avoid shooting in this situation.

The last image shows the sun inside the frame. Although lens flare is visible, it is not nearly as objectionable as that which occurred in the "10-degree" image.

Considering that these tests are closer to the "worst case scenario", the only situation where I see flare to be a major problem is when the bright light source is just outside of the image frame, but within the opening of the hood (I'd suspect that this problem would be more prominent with smaller sensors due to there being a larger angle within which the sun could hit the lens but not be in the image, unless a narrower hood is somehow employed). Keep the sun beside, above, or behind you for daylight shots and this lens should perform well.

UPDATE: I added a couple more images to show the lens off in a more realistic setting. Images of the neighbor's house, flowers, and another neighbor's lawn mower are about as artistic as I'm going to get today, but they do show great color, contrast, and sharpness. It's going to be a great lens to have around when I plan on travelling light.

UPDATE #2: Took a quick test shot with the lens indoors to test the function of the IS system. It is very good, similar in effect to that of the 70-200 f/2.8L IS system. I shot the hat at 1/40 seconds. Excuse the odd lighting - I was in a bit of a hurry and had a mix of overhead florescent and shaded light through the window. I'm providing a 100% center crop as well.