This video is an overview of the mining space. Covered is Bitcoin and Litecoin difficulty in additon to comparison of cloudmining options and hardware mining profits.
Bitcoin difficulty is growing at a rapid rate, 5 Exohash as of today. Litecoin difficulty, on the other hand, is starting to level off.
Sources:
https://www.genesis-mining.com/a/764158 Save 3% use code R3Hp4J
newsbtc.com
Bitcoinwisdom.com
hashnest.com