While the absolute prices are different from city to city, I think you can find both appreciation plays and cashflow plays in the same city. It requires knowing the neighborhoods though, an eye on upcoming economic development initiatives, etc. I've tried to diversify within Louisville, KY with these two types of areas in mind. I bought in Shawnee initially for cashflow and bought some much pricier places in Shelby Park as I believed in the path of progress/appreciation potential there. So far it's played out the way I anticipated, Shelby Park SFR could be had for 50K-80K a few years ago and these houses are now selling for 200K-250K.
In Louisville today I'd look to the Russell neighborhood, especially the eastern half, for a path of progress bet. I'm sure there are others but that's the one I know the most about.
It looks like some of the big, institutional groups have finally arrived here as well, long after the Tier 1 cities. I met one a couple of weeks ago when selling a property for my sister in Russell. I went and did a little research and according to PVA they already own 100 single-family houses (not all in Russell) and they told me they hope to buy many more.