Every market is so different and has its own sets of issues. I have been a buy/hold/rent investor. For example, I currently own properties in TX (Austin suburbs), FL, AZ and NV. I had been buying it FL, AZ and NV because they have been hit so hard I believe they have no place to go but up. If you look at the replacement costs of these properties, it will only be a matter of time for market dynamics to play out.
I use to own in CA too but sold before the bust and am just now thinking of coming back in. Different markets have different dynamics though, for example, FL has very high insurance costs. I pay 3x the insurance rate in FL from what I pay in NV. NV has the lowest insurance rates of all for me, but investing in Las Vegas has other economic risks. Plus I plan to be buying a new AC unit every 10 yrs probably. TX and FL have very high property taxes (about 3% of property value) where NV and AZ have much more lower property taxes. CA has prop 13 protecting your property taxes from going up much. None of mine are in snow country so I don't have winter problems and related repairs. Interestingly, FL is the only state where their insurance polices don't cover dog bites, who would have thought? Of course tenants never have dogs and always carry renters insurance anyway!!!!!
Obviously I am an out of area landlord and that compounds the problems. I am looking for some new areas/states now. I think there are many variables here to the initial question. For me, I have found my best market so far to be Phoenix for my buy/hold/rent strategy, but I think there are better ones, I have just yet to find them. I was in Phoenix before it boomed and came back in after the bust.