Forget pageviews, what was the click rate like between the two. It's the clicks, not the pageviews that matters. Just trying it on the same keywords is not the best test, better would be to temporarily switch out the premium account id with the standard one for a while and see if the earnings change. I wouldn't do that, though, if you are using placements on the premium site that aren't allowed with a standard account, though.
Ya I also heard alot about premium adsense account. Check this http://goa.click.in/classifieds/housing/1/41/houses-flats-rent.html I think the ads here display from the premium adsense owner. In the premium account, the freedom of customization is more and the ads look like the part of the content. So the chances are lot to get more clicks. The standard adsense account holder has some limitations. The results are less click. Correct me If I am wrong.
well my earnings fluctuate based on keyword and sites. SOmetimes, it is $10, sometimes I can get as high as $50 in a day per account. Really depends on ur traffic and keyword.
I might be mistaken, but IMO you can achieve this level of customization with standard adsense. Just set the border to white and the appropriate colors for texts. The "Google Ads" header is still there.