Mirror, mirror on the wall ... who is the best lenscrafter of them all?

I own a Canon DRebel with the 70-200 f/4L, 50 f/1.4 and the 18-55 f/3.5-5.6 EF-S. I will vouch for the Canon 'L' lens series with my blood. They are pure gems, all of them. The clarity and the tack sharpness that these lenses offer leave me failing for words.

But having said that, I was at Ritz Camera yesterday trying to find a place to print my Crater Lake Panoramic, and noticed a series of Sigma lenses which looked really impressive and probably 1/3X cheaper than the Canon L's.

I have heard a lot about the Sigma lenses, but havent found the courage to experiment by buying one. My philosophy so far has been: save up money and invest in the best (Canon L's).

Anybody out there care to share with me their first-hand Sigma experience and do a similar vouch? ... save me some serious $$ :)