My real estate investing coach taught me this from day one.....if you are looking to get into real estate as a way to gain financial freedom and work less, then there is only one answer to this question.....CASH FLOW is KING!! Thanks Mark Owens.
Full disclosure--I started doing this one year ago. I am new in this game and still learning. I currently only own 3 properties, but they are all cash-flowing $350-500/month. As long as they are doing so, I never need to worry about being forced into selling--they pay for themselves. This allows the option of holding the properties until selling makes the most sense for me. I also gain the mortgage pay-down in equity and the tax advantages of real estate to offset my gains. Its a win, win, win.
Cash flow pays your bills, appreciation does not. Cash flow creates financial freedom, appreciation does not. Cash flow provides a cushion if things go wrong, appreciation does not. Cash flow gets you your money now, not in the future (remember the time value of money).
If you have tons of cash that you are looking to simply park someplace other than the stock market and don't care about cash flow, then buy in highly appreciating areas...but make sure you have enough reserves to pay the mortgage and other carrying costs when the economy or the market tanks and you can't find any tenants. You need to also be ready to pay for that big maintenance issue (new roof, HVAC system, etc) since you'll have no income from the property.
I have done a lot of research into this topic as I was getting my feet wet in real estate, and there is no doubt in my mind that CASH FLOW IS KING!!!