The 4 channel chargers are very useful for smaller packs, allowing you to charge 4 completely different packs at once. However they're not really powerful enough to use on the larger 6s 5000 packs. If you can find a 100w version they're better but still limit you to less than 1C (4A max charge on 6S).
I tend to have two chargers, a multi charger and a larger more powerful one that will charge a 6s 5000 at 2C easily.