It's a great time for commercial real estate developers, with multifamily one of the standout sectors. In buildings with five or more units, the number under construction is at a peak since 1973, according to Census Bureau and Department of Housing and Urban Development via the Saint Louis Federal Reserve FRED data site.

But there's a downside in and around some areas, according to Brian Lawrence, vice president and relationship manager at Univest Bank and Trust Co. The success of new projects can mean a backward slide in existing ones.

"In the Philadelphia market we've been seeing a huge influx into our marketplace" with people moving south from New York, Lawrence says. "Rental rates have gone up over the last two years and one of those effects is new construction. With the new demand, there is also new construction that has gone on. Which is good for Philadelphia. You can see a boom in some tertiary neighborhoods."