I think so, of the three Sigmas I've tested, the SD9 SD14, and Quattro H
The SD-14 disappointed me the most, with its lack of consistency!
And in the end, the Sigma SD9 is by far my favorite of the three.

Sigma SD9 (2002) by Marc Aubry, sur Flickr
Last but not least, Sigma is more efficient in lens design. 😉