I’ll chime in here. I actually have a 4.2” GP100 also.
Ruger GP100:
• The double action trigger on my Ruger was almost unusable out of the box.
• The single action was just okay.
• After changing the springs, polishing the internals, and shimming the hammer, the double action is now about 8 lbs and the single action is about 2.5 lbs.
• The tool marks from the MIM manufacturing process are apparent in several places.
• The action is rugged but more than a little loose compared to the Python.
• I put Williams fiber optic sights on it and love them.
• It feels heavier than the Python even though it is two ounces lighter.
New Colt Python:
• Double action is about 9.5 lbs but feels lighter ‘cause it’s perfectly smooth.
• The single action is a crisp 3.75 lbs. It could be a little lighter but I’m spoiled by the excellent results of the trigger job I did on the Ruger.
• Out of the box the Python trigger is about as good as any new production Smith I’ve played with. So are the triggers on the new Cobra and new King Cobra.
• Only someone used to triggers that have been worked on and lightened would be likely to complain.
• Those that are only familiar with out of the box revolvers would probably say it's among the best.
• It is balanced almost perfectly.
• Lockup, fit, and finish are near perfect.
• My accuracy with it continues to improve as I shoot it. I believe it exceeds my Ruger in accuracy potential.
• My only complaint concerns the stock front sight and limited aftermarket options.
@uncle Ed - “I shoot exclusively double action.” Why? I understand practicing DA shooting. I don’t understand depriving oneself of the ease of using SA. Do you also only shoot full-house magnum loads to further increase the difficulty? Maybe try shooting with your weaker hand while standing on one leg? If that gets too easy try hopping up and down? I’m sure you’ll master it in no time. I personally need all the help I can get. SA helps.