It looks like Seth Klarman is on the same bandwith as Prem with respect to the market valuation.
http://www.zerohedge.com/news/2014-03-08/seth-klarman-born-bulls-bitcoin-truman-show-market
He mentions the same companies as Prem does, NFLX, TWTR etc.
couple of great qoutes
"the stock market, heading into 2014, resembles a Rorschach test - "what investors see in the inkblots says considerably more about them than it does about the market."
also
"In an ominous sign, a recent survey of U.S. investment newsletters by Investors Intelligence found the lowest proportion of bears since the ill-fated year of 1987".
When 2 of the greatest investors say there is an issue, i think it is time to be concerned.