Questions and things to consider about LEDS

I'm about to begin a closet grow with Northern Lights or Possibly Orange Kush. I'm ordering either a Pro-Grow 400 or a 260 I haven't decided which yet. I'll be growing in soil. Is there anything that I need to consider when it comes to growing with LED's? I've seen that some people have supplemental CFL's on the side of their LED's, why is that? Can I just use the LED's straight up? Please let me know because this is my first grow and I want it to be special.

IMO smartpot + supersoil and you are in business, with the right light, you can go straight LED no problem.