I've read very good things about what it does for eye dominance issues. I actually bought one several months for this same problem but never got to use it. Instead, I opted to place a "patch" over my left eye which has worked out pretty well for me.
If you decide to buy one, i'll send you mine for $15 shipped. It is essentially brand new since I never removed the tape backing or mounted it on my gun.
I started using one last year and it has made my shooting more comfortable. I'm right handed and left eye dominant and over the years (since '05) have tried every gadget, gimmick, black tape, 3M tape, Magic Dots, etc, etc., all with marginal success.
I have finally settled in with the Easy Hit target sight (green) and a Magic Dot. My avg's have increased and I'm more comfortable while shooting. I also use the Easy Hit on my hunting and sporting clays guns with success.