Ltcgear is my favorite.
Do they have any product that is available right now? If not than why even bother talking about them?
IMO, 20% was a good estimate for the period before June 2014.
But the difficulty increase has slowed down since then. The increase rates from July 2014 onwards are 3.08%, 8.08%, 5.30%, 20.86%, 15.03%, 8.75%, 16.20%, 0.98% and 2.81% according to
https://bitcoinwisdom.com/bitcoin/difficultyWill it speed up once again? May be. Will it go back up to 20% every 12 days? May be.
But it is hard to predict.
The next jump is expected to be 9.57% in 1.6 days thus a 13.36% rise this last month which is indeed a slowdown but this has to be averaged in with higher months where we have seen over 100% rises. Bitcoin difficulty is correlated to price and being that Bitcoin is currently bear at the moment one would expect the rise in difficulty to slow. Based upon historical data this should reverse once Bitcoin goes bull and thus one should conservatively expect a 20% average and even than run a risk of losing money.