What's better/more powerful? One hand cylinder is connected to the boost 2.0 and the other is connected to the boost cable.

Should be very close to the same.
This is just a demonstration of different age Boost gear.
On the left is Boost2.0 with the contact cable on the CS port.
On the right is Boost Cable (or 1.0), directly on Out1 and Out2.

The ONLY difference except looks and durability is the 10KOhm resistor in the CS circuit which limits current a bit, but in reality, does very little under normal conditions as the 10K resistor is very small compared to the body resistance - under normal conditions.

With the latest Boost 3.0 version, the CS connector is still available and the High Power Contact Port (essentially the same as the original Boost cable as wired on Right) is also available, so users can pick which they prefer.

For more details, please check the link:
https://www.facebook.com/groups/spooky2/permalink/775203769308195/