I'm a relatively new to the world of guns, and apart from shooting a .22 revolver (which I got pretty good at using), I don't have much experience. Basically, I'm looking for a cheap, reliable, low maintenance handgun to use for home defense, occasional target shooting, and possibly for concealed carry. According to my research, the Glock 19 and Model 10 seem to be the best choices for me. I live in California, so it should comply to all the regulations we have here, and I live in an apartment, just for your information.
I've highlighted the key elements I see here.
For someone new to guns with little experience besides shooting a .22 revolver, I'd say stick with the Model 10. This is because the long DA trigger pull reduces your chances of an accidental discharge (unless you crush bowling balls with your hands). The GLOCK's only safety is a passive safety on the tip of the trigger.
I'm biased. I've also had two new shooters blow holes in benches or the dirt near me using a GLOCK. Guns are ergonomically designed and it's all to easy to put a finger on the trigger. Unless the new shooter is going through training that stresses trigger-finger discipline, I believe new shooters should start on a pistol with a positive manual safety (e.g. 1911, Beretta, CZ, etc.)
A good used Model 10 is cheap and revolvers are quite reliable and accurate. Another positive is that wheelguns are less sensitive to different types of ammo than bottom-feeders. Light power loads don't always cycle a pistol's slide. Revolvers don't really care much about bullet shape or how big the hollow-point cavity is.
New production Model 10's come with the "heavy barrel" that most people seem to prefer. The older pencil barrel (shown below) works just as well and makes for a slightly lighter gun. Prices on used M&P revolvers is usually low - between $200 and $300 depending on condition. This
unfired 1970 specimen sold for $349.95 about 3 years ago and now sits in my safe.
S&W Model 10, 5-Inch Barrel, circa 1970.
The Model 10 is a basic, no-frills package. High speed, low drag. There's nothing on this gun to get in the way of sending a piece of lead downrange. But there are other K-Frame sized revolvers under $500 that fill your mission statement. Almost any K-frame will suffice - The Model 10,13,14,15,19,64,66 and 67 will work fine. Some have adjustable sights, some are stainless (6x prefix) and some are .357 Magnums.
Since you're in California, I will say I've discounted the CCW idea. If you live in any of the coastal counties or highly populated ones, it'll be difficult for you to obtain a permit (difficult to impossible). That may change in future, but by that time you'll be in a position to re-evaluate your needs.
If I were to recommend a 9mm pistol, I'd suggest the Beretta 92FS or M9 (the military version of the 92fs). Even with the 10-round magazine, the Beretta sits well in the hand, is easy to control and very accurate if you shoot well. For less money, the CZ-75 series of pistols is very good, if you can reach the safety and trigger comfortably.
In an apartment, your revolver can be loaded with lower-powered loads to reduce the risk to neighbors. At close range (within 7 yards) the .38 Special wadcutter can be effective and there is a lower risk if it hits a wall.