I have a mac so i can get any software really, logic is cheaper but not by much. I think ill get a midi controller if i start to get really into it they go for alot, almost as much as a software for the good ones

So im thinking about trying to produce dubstep, and i have some beginner questions. Like first off, i dont know weather to get logic pro, or abelton live. Which offers more for dubstep because that's my main focus. & What exactly is an MIDI controller? I understand if i get serious ill probably need ...