In terms of development, Brewerytown and some part of South Philly are appreciating rapidly.

Population is declining somewhat, but not rapidly, and there are new jobs being created (with higher income potential), so I don't think the population is that bad of an indicator here.  

The insanely rapid growth through gentrification and new construction in so many neighborhoods has gotten pretty out of hand, thus deals are few and far between, relevant to Columbus imo.

@Luke Andersen Luke, in order to avoid the classic “analysis paralysis” I have found it best to really narrow down your REI goals then do some research from there. 1) Figure out what exactly it is that you are trying to achieve with REI (cash flow, rapidly growing equity, etc.) 2) Next, find your niche in the market (SFR, small MF, small commercial, industrial, etc.). 3) From there, you can use a good couple hours on Google to find maybe 4-5 markets that match your criteria. 4) Once you find these, try to dig into specific neighborhoods and find out crime rates, school zones, walking distances to places, etc.

I'm in grand rapids and starting to see some good deals come up.

You can begin by weighting factors of each property condition to a whole rather than individually.

I work at an investment advisory firm in Denver and we help clients invest in Kansas City, MO and Grand Rapids, MI. 

The one I am closest on is a 4 unit in a rapidly growing town with under market rents in prime location.

I understand Grand Rapids is growing in a more faster pace but the cash flow seems to be hard to obtain (still I am not ruling out that option just yet either). 

So you'll have to weight the risk vs rate that you can get.