Stay away if you can. Go for the 6.6 Duramax or something.
We bought a diesel suburban two summers ago to go on a trip. In one trip this is the list of replaced items and how many times they were replaced in one weeks time.
glow plugs x4
head gaskets (didnt even need replacing)
6 out of 16 lifters
It was all (besides the A/C) attributed to one problem: hairline fractured block that was there when we bought it, no dealer/diesel specialty shop from here to Denver could find it.
All this happened on one 21 hour trip of constant driving carrying a 14,000 lb load:
1)Engine heated up, crack expanded
2)Coolant leaked into the combustion chamber/oil
3)Coolant filled oil got into the turbo bearing thus causing a catastrophic failure
4)The oil from the bearing exploding was sucked directly into the intake/combustion chamber causing enough pressure to crush some of the lifters.
5)The engine cooled while being towed so the crack 'resealed'
Not a single professional could figure out how everything happened so we would get one part fixed then when it wasn't fixed we'd take it back for another Finally the crack expanded enough to be detectable many months later and the engine was replaced.
'94 Bonneville SE - 106k miles 6/1/07