I will set up a poll, title says it all, vote for the better magazine, my vote goes with diesel world, because my truck was in it.
I have not seen Diesel World yet, but between 8-slug and Diesel power, Diesel Power wins hands down. If I was looking to build a trailer/mall queen or shopping for specific beauty items for my truck, then I might open the pages of 8 lug. 8 lug's focus is bolt ons for your truck available from their advertisers and other vendors (which is not necessarily a bad thing and there is a market for it), but I like the history of diesels, diesel technology (whether it be car, truck, boat, plane, scooter, etc.), Tech articles on engines (not how to's on bolt-ons), and 8 lug does not focus on that (at least not what I've seen so far when browsing the magazine racks).
Just my opinion though and we all know what opinions are like.
If anybody sees Diesel World in the New England region, please let me know as I would like to see what it has to offer.