Jim Cramer, the host of CNBC's Mad Money, has been buying REITs since June, seeing a tremendous value opportunity in the beaten-down shares of companies that were in the process of rebuilding their balance sheets with new equity. "You haven't had this kind of wholesale price decline and hatred of the group since 1990. That turned out to be a great time to buy REITs. If you bought the ones that were going to survive, you ended up making a ton of money, and I feel the same way now," Cramer told Real Estate Portfolio. He singled out as his favorites Brandywine Realty Trust, Vornado Realty Trust, Federal Realty Investment Trust and Boston Properties.