There are absolutely zero concerns about Glocks chambered in any caliber, much less in .40. There are probably more .40 S&W Glocks in holsters for LE agencies throughout the US than there are of any other firearm. Further, there is no reason to believe that there is any difference between the 23 and 19, specifically.
If you don't have an agency based requirement to be using .40 S&W, and you don't need the slightly enhanced barrier-blind quality of .40 S&W, particularly on auto glass, then the 9mm is the clear choice. There is a reason that the Glock 19 is the most ubiquitous modern handgun in the world. My issue firearm is a Glock 22, but I carry a Glock 19 on my own time.
For the sake of ease of shooting, and the cost of ownership, 9mm is the better choice.