If this is purely a self-defense/concealed carry pistol, my recommendation would be to not waste your money.

The red dot will be of no real value in any likely civilian self-defense scenario involving using a concealed firearm due to the compressed time frames and close distances. Suarez himself has essentially said the same in numerous statements.

If proactively engaging terrorists and active shooters is on your list of things to do, then it might have some merit, but I would recommend going with a different pistol altogether rather than a tiny, single stack Shield.