It looks as though Freddie Mac has a positive outlook for multifamily housing in 2014. The expectation is that the rents and vacancy rates will keep up with the average growth momentum and for some of the more depressed areas to improve.
Here is the full Freddie Mac 2014 Multifamily outlook (PDF).
In their opinion a strong employment growth has fueled a strong demand for multifamily housing. I do not agree with this assessment. Many past homeowners who lost their home between 2009 and 2012/13 have been the main fuel for the growth in multifamily housing. Many of the families are still not able to afford buying and many were forced to move in together due to the lack of income of either the parents or kids.
I do see continued growth of the multifamily market sector and the single family sector is beginning to improve.