If you don't shoot the gun, you have no attachment to the gun then I would say sell it. The only guns I own that I do not shoot were given to me by family and have a value to me personally beyond being just a gun.
The Glock, Sig, M&P discussion is one I don't understand. High bore axis, low bore axis, Single/double action, hammer/striker etc. I own them all and I like them all. Honestly, maybe I am just a horrible shot, but I can shoot them all just about equally as well (or poorly, depending on your perspective).