I've really liked both issues so far. The art is pleasing to the eye, and I think the characterizations of Cap and Supes are (almost) just right.
I also appreciate the fact that Cap is established chronologically as the third major super-hero, before Wonder Woman, Flash, and Green Lantern -- it is actually consistent with his real-life introduction. (It does, however, mess with continuity a bit. Does this mean that Billy is now something like 20 years old?)
I don't think Scott Cooper was previously introduced as such. I have heard speculation that he is a revamped version of "Steamboat," a friend of Billy's who was portrayed as a rather unfortunate caricature.
I like the depiction of Dr. Sivana -- and I'm excited to see how Cap and Supes will handle the combination of both Sabbac AND Eclipso.