Are you referring to the Apex kit or just the trigger assembly? If you are referring to the Apex trigger itself, that's personal preference. I will say the over-travel stop is more solid on the Apex. In the stock M&P trigger the over-travel stop is that little tab at the bottom of the hinged lower. It contacts the stop built into the floor of the trigger guard.
The Apex trigger is one piece construction, not including the safety disconnect that can be removed if one is so inclined. The trigger body contacts the frame for over-travel. It's more solid and over-travel can be adjusted through the trigger bar. Mine are set up to break towards the back with only slight over-travel.
Not being a fan of the glock trigger type, I still decided to try a polymer Apex trigger on one of my M&P 45s for the reasons above. The polymer can typically be found for ~$40. The pull is different than the glock and the safety tab is not as noticeable. The more I shot it, the more it grew on me and now all my M&Ps have the Apex trigger. All my M&Ps, except the Shield 45 have the apex internals as well.
As always, YMMV and it is personal preference. If you are curious, pick up a spare trigger bar and the polymer Apex trigger and give it a try.