I have experience solely in Ford land. I have a 2005 F250 with the 6.0, I did replace injectors at 80k, I did by it used by the way. I then bypassed the exhaust enviro stuff and have had no issues so far. I have pulled WAY over the suggested weight limits and probably been lucky on head bolt issues as my diesel guy wants to "bulletproof" it.
I had for 3 years an 08 F450 DRW with the 6.4, only had one sensor issue, but only put 40k on it while I had it.
I now have a '12 F350 SRW with the 6.7 and so far have had no issues, again diesel guy wants to revamp the exhaust due to his claim that this is the cause of all diesel engine issues.
As with anything, there are those that will have no issues and sometimes people who have all kinds of issues. They are machines and can certainly break.