I installed my apex kit. I spent $102.00 with shipping. Is it worth it? Not sure? I test each component as I installed them. With the USB, hard sear installed, the trigger was lighter but a little mushy. I installed the sear spring and that felt the best out of each of these combination's, but still a bit of a mushy trigger. With the trigger return spring it's basically the same but with a heavier pull. All in all the kit is not going to make your M&P feel like a good 1911 trigger, but it does lesson the poundage a little. If you leave off the trigger return spring then it does lighten it a bit more.
The kit was easy to install EXCEPT the sear return spring. If you're not careful you will lose your spring plunger.
102.00 dollars might be to expensive for this kit, but that's up to you.