No I have never used them. I never had the need to as I don't live in MA so all the M&P's I owned had the stock trigger pull of 5-7 pounds. You can get a trigger job to drop the trigger to as low as 2.5.
Have you reviewed or had any experience with the new Apex trigger system for the M&P's yet? https://apextactical.com/store/product-info.php?pid35.html