I did a lot of research before buying my 2006 Duramax... I love my truck!
I love the Duramax Engine, 6 speed Allison transmission and no DPF fluid needed! I bought it with 180K on the clock and have had 30K of no issues so far!
I had planned on buying a 7.3 powerstroke but all the Ford lovers wanted much too high of a premium for them. The Duramax was just a little more than a 7.3 Powerstroke and I firmly believe the Allison is much better than the transmissions that came behind the Dodges and Fords of the period.