Honestly man I wouldn't even bother with mining. In this day and age ROI is pretty shit and you're likely not to make anything by time you factor in electricity and whatnot. Mining isn't a game for consumers anymore but for large corporation that have centralized the BTC mining POW.
Honestly better just to buy BTC and invest them somewhere.
Curious, what is your idea of a sound BTC investment? Gambling or signature campaigns?
Gambling is a horrible idea it's not a investment. It's something you might enjoy if your a gambler but in no way is it an investment.
Signature campaigns are kinda a bonus. Just post normal and you get a little extra coin for posting which is nice.
But neither of the two things mentioned above are investments. For what it's worth I think mining still has some life in it. Just is longer ROI and harder then it once was hen 3 month ROI was normal.