As long as you don't want to look back they're fine...
I thought they have this miracle convex that shows you not only the road but a glimpse of your past as well ? are you saying the marketing over-stated the reality ?
I went the Arlen Ness Rad III mini's....from the stock HD's they are big cut down in what you can see. Saying that I'm surprised how much I still can see. Though no matter what mirror I use , big or small, I still have a habit off always turning my head to look behind