In that case, Apple’s is good in that the charging battery has cool smart integration with the OS like Airpods. Apple’s also works as a 15W MagSafe charger if you leave it plugged in so it’s neat if you don’t have any other magsafe chargers at home. Lastly, it is the only Apple product that can be reverse charged: when iPhone is plugged in already, attaching the battery starts charging it instead of the phone.
Downsides: Apple’s battery only charges a Max sized phone about 30% so not amazing, though good for its size. Also, it only charges at 5W when used by itself. To get the 15W speed, it has to be plugged in to a cable and used like a MagSafe wall charger.