The folks over at Warhammer Community have detailed a few of the different tactical options offered when you come across a double turn situation in Age of Sigmar. Far from simply looking at the positives, the article also goes into the times where it may not be best to utilise it.
In Warhammer Age of Sigmar, the double turn is as strong a strategic advantage as counting on the double turn can be a deathtrap. Make sure you prepare for both possibilities and always be aware that by taking the double turn, you set your opponent up for potentially getting one of their own.
Matthijs – Warhammer Community
Source: Warhammer Community