I have an ATI Scorpion on mine. Have tried the Magpul as it came fitted, also had the A2 style in my hands previous. Also have Hogue fitted on other rifles with storage and finger grooves.
I like the ATI on my Smith, love the Hogue on others. Not a fan of the A2 grip, will likely stick the Magpul back on at some point just because I can....
But not yet.
Rob.