My general impression about mining is that right now it's a horrible idea to get involved in it as the necessary investment/expertise keeps increasing and there seems to be a problem where there's a big pipeline of already-paid-for ASICs which cannot justify their purchase cost but where the least lossy strategy is to run them and recoup as much of the loss as possible (which pushes up the difficulty massively and makes additional capital investments awful ideas). If one wants exposure, buying bitcoins seems like the best approach right now.