Based on the most recent rental survey conducted by RealFacts, covering over 13,000 rental communities in fifteen states, results indicate there is a preference for the northern US. Strong apartment fundamentals continue to rage on everywhere in the nation as they have since early 2010. But premium rent growth is sky rocketing in the northern part of the country. San Francisco, Denver, Portland and Seattle are beating out their southern counter parts---Los Angeles, Houston, Miami and Phoenix.