New around here myself! But 13?! I only have 2 :p... But when I stop to think about it, they're not a bad investment.. or experiment.. we'll see in a few years if they make their $ back. In the end it's a way of getting bitcoins without having to make an exchange, although much slower.
Have you seen recent 2 diff updates? >30% each
Even before them calculators with diff taken into account were showing ROI: NEVER.
Few years? They will be useless after 12 months because of diff (you will be paying more for electricity than recieving $-worth BTCs)
Above sentence can be untrue if BTC price will rise significantly but it doesn't change that it was a bad investition because you should calculate your ROI in BTC, not in dollars. Even with price rising and being still profitable after a year you would make MORE with just buying directly BTC and selling them after a year. Think about it.
ASIC ERUPTERS ARE BAD INVESTITION BECAUSE THEY ARE OVERPRICED. I'm amazed how people still buy it massively... Greed?