It seems nobody here is in the position you're in: you have both lenses and can test it out yourself. So just keep them both say a half year and keep switching, until you have an educated opinion yourself.
But yeah, the L lens is more likely to be the winner of such a contest.
Besides, you can also always check out the respective flickr groups, to get a "feel" and impression for a lens, even if you dont own it.
About Canon L lenses, they are intended for professionals, and are very expensive, while their non-L are for hobbyists. While of course all companies have lenses of different prices, I know of no other photographic company that does such a harsh distinction between first rate gear for professionals and third rate gear for hobbyists. Many amazing photographers of times past have been hobbyists, like Miroslav Tichy and Vivian Maier. And any hobbyists can get as good as the professionals if they put the work in to learn the trade. Thus assuming that hobbyists should be rich or use second rate gear seems very arrogant to me.
About sharpness tests from DxO, they are completely useless. They only test one focus distance, and they dont correct for curved focus plane. Which is why some lenses with sharpness issues receive great ratings, while other lenses that have curved focus planes receive poor ratings, despite being super sharp even at the border.
