It's Solid... Surprisingly I was able to order the Different size Grips from Springfield... including the new FC Grip which makes it like a G19X... The 4.0 comes with the Small Grip.. Med is perfect.. the Large feels more like a Glock Gen 3. I also got a couple single sided mag releases before...
Different because it's rubber... but still good. Shoot it for a while without it.... then try it. You'll see what I mean. It just fits the hand better with it. It's more like a full size grip and more comfortable to shoot.