I installed a Ghost Ultimate Kit in a Glock 17 that I had and it was a night and day difference. By far the best upgrade I could have made on that pistol. I will say that I wouldn't have felt comfortable carrying the Glock with that setup because it really did make the trigger significantly lighter and more snappy. Mine was strictly a range/home defense gun so it didn't matter. I wouldn't suggest putting it on a small conceal gun for safety and, potentially, legal reasons.
But for general use, it makes a heck of a difference!