That's a very decent kit, and the price is pretty good.
I generally prefer to put my softboxes on open-faced instruments though, rather than the bare-bulb type setups like this which are made specificially for softboxes.
I find that the light result is about the same, and if for some reason I dont NEED to use the softbox (if I want a harder light), I can always yank off the box and throw on some barn doors and I have a conventional hardlight... rather than being "stuck" with having to use the softbox because of having to use the instrument inside.
But yes, if you KNOW you want it soft, and size/weight/traveling is a consideration, it sure might be the way to go.
Fantastic Plastic Entertainment, Inc. fantasticplastic.com
I agree that using a bare bulb system seems a waste of a lighting fixture. You may have need to use that light for something else while shooting b-roll, etc. Also, how well does the bare bulb fixture travel? I assume it has a case of some sort.