It can't be that much more than the 3rd party unit. Whatever the actual weight is, it's not enough to where you would notice an increase. We are talking about ounces, not pounds.
It adds some weight to the camera, but with a good neck strap you won't even notice it. Also helps to offset the weight of my lenses. It's made of magnesium so it will be heavier than the 3rd party grips.
You justify it by how much better it feels and fits in the hands. Also, holding an extra battery means you likely won't run out of battery in the middle of shooting.
You justify it by how much better it feels and fits in the hands. Also, holding an extra battery means you likely won't run out of battery in the middle of shooting.