Half the time, when I turn the camera vertically, I forget to use the controls on the grip. Frankly, I think they designed it poorly by putting the shutter release on the right side of the grip. I think it would be more natural on the left side, but that may be just me.
I'm confused by this. The normal shutter is on the right side of the grip.
Hmm... strange indeed.
Not strange, but perhaps I'm not explaining myself adequately.
Years of shooting with film cameras taught me to rotate the camera clockwise for a vertical shot. It is much more stable, because the right hand supports the weight of the camera from below, while also allowing you to operate the shutter button. This leaves your left hand free to support the lens (and focus and adjust the aperture in the "old days.")
But, with the Canon grip, you have to rotate the camera counterclockwise to use the grip's shutter release. That means that your right hand is suspending the camera body from above, not supporting it from below. It has the advantage that you are still using your right hand to fire the shutter button. But, it feels unnatural and less stable to me.
It is hard to break nearly 40 years of habit and as a practical matter I find myself seldom using the shutter release on the grip. My hands just naturally turn the camera clockwise and continue to use the shutter button on the camera. It's not a big deal.