Frankly I don't like this idea of Superboy prime as the villain - maybe I'm being a unidimensional fanboy here but I absolutely hated the fact that Superboy is now a villain. Of all the pantheons of Big Bads that are available in the universe why did they have to go with taking a "good guy" and turning him bad?
I understand how this is not the Superboy that I remember reading all those Smallville stories about and that Crisis on Infinite Earths changed it and all that. But still... Superboy is evil?!!
Having gotten that rant out of the way - I also have read only a few tie-ins to Infinite Crisis - I would really recommend Identity Crisis since I really liked that book. It was a tightly plotted and human story. I have read Omac Project and I know it was important to know who's behind it all and Brother Eye and all that jazz. But it just didn't work for me (imo). Partially because I didn't know half the people in it. I have read the IC Companion and I liked it.