My 07 Classic Silverado 2500HD LBZ Duramax Allison 1000 6 speed is without question the best, most powerful pickup I have ever owned bar none! But rather than getting into the pointless which is better argument, I recommend you go drive all three diesel pickups and make your own decision. I also recommend you check out Diesel Power magazine, it is packed with good information every month on all three brands. There are also tons of diesel pickup forums that you can browse. Being a D-Max owner, here is a link to just one of the Duramax forums that I frequent which has a huge membership.
http://www.dieselplace.com/forum/index.php
Just be aware that diesel engine technology is changing rapidly and any comparisons to older trucks, even 10 years old, is irrelavent to current model discussion. All of the big three have weak points, all of them!!!
There have been tons of comparison tests done in different formats, but in my opinion one of the best real world tests was done by Diesel Power Mag where they took trucks from each of the big three, hooked each one to a 19K+ trailer and took them on a 2000 mile trip through the Rocky Mountains including their famous King of the Hill pull. You can watch the video here.
http://www.dieselpowermag.com/featur...deo/index.html
Early 2011 King of the Hill test. The interesting thing about this test was that the Dodge had too low of a GVW rating to be able to participate with the GM and Ford. Basicaly the Dodge was outclassed before the test even started.
http://www.dieselpowermag.com/featur...uty/index.html
The current models of diesel pickup from all three manufacturers are the most powerful ever built while still meeting EPA regulations. People can argue which is best all day long but the bottom line is that you will not go wrong with any of the three. As I said earlier, drive all three (preferrably towing a heavy trailer if they will let you) and then make up your own mind. Just beware that these diesel trucks make so much torque that they will litterally erase the tread on drive tires if you tow alot, ask me how I know.
BTW, here is my Duramax.
