Without tools for controlling and shaping the output of your lighting instruments and the sun, you will never be able to get consistently great results on-screen. This set of flags and scrims looks to be a tremendous value. As long as you have some C-stands or at least light stands with grip heads, you should consider adding this kit to your toolbox. The best thing about it is that it is super-portable, although I am not sure how durable it is for everyday use on-set. Knowing the track record of Digital Juice, I am optimistic in that regard as well.
Learn more about the DJ Flag Kit by visiting their site here.