OP I have a 6.0 and very pleased with it. I have owned 2 thus far and have no issues. GM did a great build on this engine, very reliable and pulls without and complaints. I sold my last one with high miles and it had been worked its entire life. Only issue was CPK sensor, fuel pump, and exhaust Manifold studs other then that I changed the oil, coolant, spark plugs and filters. Replaced the water pump and CPK sensor as well. On the newer generation one that I have, I have not done a thing. Only maintenance items only, filters and oil change. I really like the newer one with the 6 speed auto. Yes you will find several older 6.0 engines with well over 200k with a lot of worked miles. So my personal experience has been great with these engines.