You already have a lot of information, but to chime in here a bit…..
Glock are fine pistols, but .40 (like Whirli said) is not as fun to shoot as 9 mm. It is like taking out a .357 and shooting .38 spl in it. You can plink all day long with the 9, get good with it, use less money in ammo expense, and they just seem to keep going. They remind me of the 10/22 to some degree.
I also am not a Glock guy. They are made for people with hands and not paws. Instead, I like my Beretta 92a1 for my combat pistol or my Para 1911. My wife has a G30 that she loves and can hit things with. It has been tossed around our family since 1998, so it can take a beating. I have no idea how many rounds have been put through it either, but it just won’t break or quit functioning.
$540-ish is a good price for a solid pistol platform, but I long ago “poo-poo’ed” the .40 for my own use and thus recommend 9 mm.