Gotboostvr, I just saw your post about how much you like the standard AR grip. I too ground off the ugly knob, but I also added some self sticking anti-skid tape (3M) from our local Ace hardware. The 1" wide strips fit perfectly on the front and cover up any signs of marring from where the knob was. It gives a sure grip and can be added to the back of the grip if needed.
In a couple of days I should be receiving a new "Friends of the NRA" M&P15 Sport with 1 in 8 twist and 5R rifling. For now I will put a Bushnell TRS25 on it, install a light and modify the grip. Later I might add a Vortex SPARC II but will leave the rest alone.
Try adding the tape because I think you will really like it. If not just peel it off and and you're good to go.
Take care and good shooting.
Stormspotter