Well speak for the US. We don't have suburbs in Brazil. In our big cities, houses are in mildly dense areas and our city's surroundings are slums. In any case, that doesn't change the fact that from my personal experience houses are much prone to being broken into even in less urban areas.
And pretty much every apartment building here has at least two gates and multiple cameras in public halls and elevators. Gatekeepers are very common but not a must. Fancier ones have ID card/fingerprint recognition systems database on top of that, so like, yea.
I think it's fairly easy to say urban areas are more violent and have more crimes, but those don't necessarily mean they're crimes regarding your home's safety, as a good chunk of these numbers is probably pickpocketing/robbery.
Fire is a fair point, people knowing my routine better because they live next door is paranoia. Apartments are just a bunch of stacked houses, the interactions between neighbors are almost as limited as if it were neighboring houses. Unless you're actively stalking them, which could happen with houses as well, you'll barely know anything about them, lol. I can tell you I know nothing about any of my neighbors except that my upper one seems to have frigging zoomies at 10 PM and goes running around his place for some reason.