Concentrate or diversify?

[Joe Kling]

Hey BP!

For those of you who've gone the out of market route and are investing outside of your general vicinity, let's say for this discussion far enough away to mandate a professional property manager, are you concentrating all of your investing in one market or are you diversifying your portfolio? 

What are the pros and cons of your approach? Economies of scale? Less volatile in terms of both property value as well as general economy of the market? 

What are your thoughts?