I'm tired of hearing so much negativity when it comes to mining bitcoin and alts. For the Antminers, in particular, people continue to say that they don't produce a "ROI". That's just so much BS and FUD spreading...STOP IT!
I've done a ton of research on bitcoin and litecoin mining (using ltcwisdom.net) and even with serious increases to difficulty on a weekly basis (based on average increases) and, again, assuming the price of the coins don't drop extensively, you can BREAKEVEN (stop saying "ROI" when you mean BE by the way...you can have a negative ROI...so when you say "you won't ROI" that doesn't make sense) in 7-9 months on a L3+. That's worst case scenario. Best case is 4-5 months breakeven. Then, after that, it's ALL PROFIT. What is so bad about that if you have 15 machines? So you wait 4-5 months until it's paid back. And yes, maybe you're not making as much as when you first got the machines due to difficulty but you're sitting on passive income.
Same thing goes for the A3....oh boo hoo you're not making $500/day. Boo hoo you're not making $50/day. Even making $10-15/day when the machine costs $1,000 is worth it assuming you can get for a month or two. Even if you only get that rate for a month, you're paying off at least 50% -75% of your investment. That's the risk you take....
So please stop spreading FUD - we know you just don't want competition...too bad.
End Rant.
i worked in mining and now i am mining monero but mining is so difficult job that you must consume hardware and also electric power, and if you check the mining process u will find out that the heat of mining like Heater. you need some external cooler to cool the mining room. and other disadvantage of mining is that, you must hold your coin to reach a good point vs BTC or $. some of devices will had been some problem with rigs and also other problems. so it seems that some one prefer trading or other ways to earn money.