Like any transaction, you need to do your due diligence.
I have known several people (buyers & sellers) that have successfully used rent/lease to own contracts- though in the last couple of years Jim is correct that the would be buyers haven't fared as well; but then again neither have the vast majority of traditional buyers (many of which have had losses in equity greater than $25k & $50k).
Now that most markets are starting to stabilize (and some are starting to even see increases in sales and home prices, less inventory, and increasing rents) you may find a rent to own contract a useful tool in your quest to buy a home.
Before you start looking for rent to own opportunities: I recommend that you speak to a reputable lender in your area. Find out your credit scores (get a copy of the report) and what you need to do to increase it. Find out how much of loan you will be able to qualify for & how much you need for down payment (for an FHA loan the down payment starts at 3.5%!!! & for Homepath eligible homes only 3%!) and closing costs (usually between 4-6% but some programs like FHA allows the seller to pay them for you!). If you are low to moderate income, ask if you qualify for any county or city programs (not all lenders do them so you may have to shop around).
After that you will have a good foundation to start looking at homes whether it be to buy, rent to own, or just rent.
Whatever you decide, I also recommend getting an agent that is knowledgeable in what you want to do and good at negotiating to help you achieve your goals.
Best of luck,
Century 21 Showcase
NMLS # 6395
Financing Kentucky One Home at a Time