One shortcoming is located DSSS the charging current via power supply at 150 mA and is very hot, it's just a small travel charger, better connect directly to the MacBook, then the charging current at 1000 mA, then the battery is full in about an hour.
One thing applies to all batteries that power the 4K mode is less than 40 minutes, is because that in the 4k GoProHero4 why is very very hot and the battery, as a result, battery life goes down when a lithium battery is hot.
Generally always recommend via laptop via USB to load because the power dissipation at its lowest and the charging current is highest, the charger will then not even hot and via USB output can even mobile phones are charged, for example if only a mobile phone USB Charger is available.
What I also highly recommend in mobile use, for example to operate the charger via a mobile power bank, then you can go for example to charge the Outdoor GoPro battery again within an hour.
Optimal was the usual fast delivery.