When Margalus ran SouthSideSox, it was a bit more of a free-for-all, and people were carrying on for days when Jake Peter was traded, or Jordan Guerrero wasn't added to the 40-man for Rule 5 protection. I think Jim has always had interesting and inciteful takes, and the comments at SoxMachine are more intelligent. Josh has always just droned on about the outrage du jour in his lowbrow, meathead fashion.
Jim and James Fegan offer the most focused and in-depth analytical discussion of White Sox issues of any blog, I've found. Everybody else just seems to be recitations of the latest press releases and listicles, whereas Margalus will put forth a thoughtful article on how the trade of Aaron Rowand for Jim Thome was the beginning of a decade of ill-conceived maneuvers to fill the gap in CF they created with that trade.