they all have little issues that are pretty easily corrected... wow that doesn't sound too good...
but seriously, the 2006-2007 LBZ is the "best" yet.
the 01-04's had some injector problems (most of which are fixed under warranty) and the 04.5-05 had some thermal breakdown issues.
I have a 2005, and with a couple hundred bucks you can make them run quite well.
its all about what you want to spend. if you can afford an LBZ go that route, if not, they are all great trucks.
Let me know if we can help.
Jess