I would just purchase a Glock 19 Gen4. Keep the .40 or trade it in, but stick with Glock since that is what you're used to. Why have to start all over with an entirely new pistol? Now if you just want a different make for recreation, etc., then sure, do so, but if you're going to continue to work with this pistol, stick with what you already know well. I carry the G19 G4 and love it! The recoil is very low, and it fits my hand perfectly. If you're used to the G23, it seems to me to be the most logical transition. Good luck!