My grips is what saves the camera (together with the Panasonic micro 25/1.4). It transforms the camera from good but too small and too cramped camera into a good camera which easily can be carried around with no risk of slip out of my hand. At the same time it also make it fiddly to switch battery and press the button on the top of the camera. A small detail worth mentioning is that the tripod mount now is aligned with the optical axis.
I wish the grip was built in and now when it is not I wish Olympus had given us a way to configure the now redundant shutter button and front control wheel into something else but just doubling the functions on the grip.
I use half the grip only, sometimes called landscape grip) and everything said above is valid for my hands only.