The BEST quality injectors are Motorcraft. I have a Hickok G2 tester (check it out on youtube) and have been using it for years to test these trucks for years, the tester don't lie! The 6.0 engine runs sooooo nice when it doesn't have a stiction issue. A new Motorcraft will have 245-255ms delay, even at -10*F, I know, I've tested them. At 350ms delay Hickok says they fail, when the injector is >300ms delay the engine will run "acceptable" to most people. When you start a 6.0 cold is when you see the most stiction, then it goes down from there. I tested a truck with a brand new set of "popular" brand rebuilt injectors, that the company rep said were "the exact same as Motorcraft", 7 out of 8 failed with more than 350ms delay on the spools. They paid the labor on that claim and refunded to money.
There isn't a scanner that I know of that can diagnose stiction, and a cylinder balance test is useless for stiction.
After using this tester for years and testing many trucks, and trucks for other shops, I will NEVER put ANYTHING OTHER THAN A MOTORCRAFT injector in a 6.0 engine period. I hate to do something twice.