Juli Clover, MacRumors:

There are two kinds of 5G networks: mmWave, which is the super-fast 5G that most people are talking about when they talk about 5G speed improvements, and sub-6GHz, the 5G that most people are going to experience for the time being.

This is a great explainer, to help you wrap your head around what’s coming, the terribly named mmWave and sub-6GHz.

Apple employees that have been testing the 5G iPhones recently (and confidentially) told Bloomberg that the 5G speeds have been disappointing as the current 5G networks are not “improving connection speeds much.” Most people who are expecting their iPhones to deliver super-fast mmWave speeds will likely end up similarly disappointed when they find that mmWave networks just aren’t available in most places.

Set your expectations accordingly. At least in the US. The way I read it, this is about telecomm infrastructure rollout, not Apple’s hardware.