I just finished two books in podcast form, Earthcore and Infected by Scott Sigler.

Both books are good, but I enjoyed Earthcore more. Earthcore is about a mining expedition, and the trouble it runs into when it goes very deep. The characters are strongly drawn and appealing, and the underlying mystery is interesting up until the end of book. The build up is relatively slow, but is interesting along the way, and once the action gets going, it was hard to stop listening.

Infected also kept me engaged, but has fewer characters and the situations are more difficult to read about. At the beginning of the book, it's about the investigation of a mysterious disease that is driving people mad, leading to mass killings. But the bulk of the book follows one of those people, as the disease progresses through him and he struggles against it. That progress and struggle are hard, and at times very gross reading. And for me, the payoff at the end was not very surprising.

I'll definitely follow up with some of Sigler's other books.