I imagine the difference would be in the lower pressure of the conti's, and also I think they are wider than the tires you removed. The Conti 28x1 1/4 were sold to me as 700Cx32's so that would be larger than your 28's.

I didn't notice much difference from my old tires, except the new ones have tread left!

Did you have any trouble getting them on? Mine were really tight on my rims, although the other tires were as well.