I'm considering building a USB mining rig, but I fear that at this point it is too late to make any profit.

If I go about buying, let's say, the Bitmain Antminer, which runs at 1.6 gHs/s, at the cost of $85, would that return my investment?
I would buy one, mine, profit, and then buy more, but I fear that with the current and coming difficulty on the network+the global hashrate, it would be a folly.

What do you guys think? I would buy one of the big ASIC miners, but yeah... Can't make bread without dough! 

Excuse this blasphemous question, but would it be a better investment to mine litecoins, from my standpoint? I have a 7870 card.

Cheers!