Is the Amazfit Active 2 Square good for running?

Yes. It has built-in GPS, heart rate tracking and a barometer for elevation, which covers pace, distance and route data. The leather strap is the weak point, so swap it for a silicone band before sweaty runs.

How is it different from the round Amazfit Active 2?

The main difference is the square case and screen shape, which shows more text per line in notifications and workouts. Health and GPS features are otherwise the same family of tracking.

Does it work with an iPhone?

Yes. It pairs over Bluetooth and the companion app runs on iOS. Some deeper integrations, like replying to messages, are more limited than on an Apple Watch.

It is water resistant, but the leather strap should not be worn in water. Switch to a silicone or nylon band if you plan to swim or shower with it.

The watch with its leather strap and a magnetic charging cable. A spare band is not included.

Is the sapphire glass worth it?

Sapphire is much harder to scratch than standard glass, which matters if you wear the watch daily against desks and doorframes. It is one of the main reasons to pick this model over cheaper plastic rivals.