Pros:

-28mm on a 1.6 crop camera (like my Canon XT) is 44.8mm - almost a 50mm normal lens!  My new walk around lens.
-I love the warmth Sigma lens impart into their photos.
-Fast, fast, fast!  F1.8 gives such beautiful out of focus areas and low light shooting.
-The price

Cons:

-The focusing tends to slap around, especially if it's hunting, which it is won't to do if the battery is low or the lighting is less than ideal.
-The lens cover falls off all the stinkin' time.  I bought a replacement for ten bucks and never looked back.
-I didn't think the two step manual focusing would bother me, but it does.
Pros:

-28mm on a 1. 6 crop camera (like my Canon XT) is 44. 8mm - almost a 50mm normal lens! My new walk around lens. -I love the warmth Sigma lens impart into their photos. -Fast, fast, fast! F1. 8 gives such beautiful out of focus areas and low light shooting. -The price

Cons:

-The focusing tends to slap around, especially if it's hunting, which it is won't to do if the battery is low or the lighting is less than ideal. -The lens cover falls off all the stinkin' time. I bought a replacement for ten bucks and never looked back. -I didn't think the two step manual focusing would bother me, but it does.