Relapse and Refill... What's the difference?

When everyone was talking about this album being released, I was excited and got it as soon as it was released but it's pretty much the same as Relapse with some extra songs.

I bought both Relapse and Relapse Refill because i'm a really big fan of Eminem (he's my favorite music artist) and I buy every album and single he releases but for those of you who aren't really big fans of Eminem then I would suggest that you just buy Relapse Refill because the whole Relapse album is released on Relapse Refill as well as on its own.