I have a Speed graphic and focus to groundglas is great but i would love for faster action to use one of those but i am not sure how good they work.

One as the cambo one eye finder


the other is a Horseman / polaroid where you look with both eyes


I know thay sometimes not fit but there are adapters for that. So is it polsile to focus acurate and how the image looks like.
So i am not sure wich one is better..Pro & Contras?