Had a horse trailer delivered to me last month. Hauled in by a 05 Quad Cab 4x4 auto. Had 559k and change on the odometer. Owner said injectors had never been touched. In fact he said NO major repairs of any sort.
I think they're better than what I expected. At 30k I installed a 100hp pressure box. Not a good idea. After about 75k, mileage went way down; 12-13 at best/towing 9-10. After 100k, I pulled them out, 2 cracked, 4 good. Replaced nozzles with 50hp. Runs smooth now. 118k currently.