Using 5 x 105w compact fluorescent daylight balanced bulbs at 5400k in each head which gives out the equivalent of 420w of a normal household bulb, the way this is calculated is to multiply the starting wattage by 4 and this would apply to all of this type of bulb. Some companies will multiply the wattage by 5 times which makes it look like there equipment gives more power than it really does, so find out the wattage of the bulbs they are using and do your own calculation, some of these companies are not small ones either.
In the Supersoftbox 5 kits go up to a three headed kit, the 2 head kit and 3 head kits are suitable for full length portraits and for video lighting quite a big scene, on the back is 2 switches to allow 3 bulbs to be lit or 2 bulbs to be lit, the will also work with not all the bulbs in place.
We have produced a video overview of the Supersoftbox 5
We also have our very popular 3 headed Supersoftbox Kit