From my own experience (I've owned one of each, tuned and untuned) they make a huge difference, they're smoother, will feed anything, more accurate and have an amazingly nice trigger. My Armco tuned Compact has over 6,000 rounds through it, and hasn't had any failures of any type, it's also accurate enough to put 8 rounds into the head of a B27 target at 25 yards. Given that you're really only paying the cost of the trigger job, they're a great deal. I couldn't see myself asking much more (practically speaking) out of a gun that cost 2 or 3 times as much - you get the accuracy and dependability of a Kimber or Colt with the ruggedness and low cost of a Norc.