IMO, flipping makes sense in certain markets where there's both a good supply of distressed properties and demand for nicer properties. Profit from flipping depends on one's ability to find deals and move a large volume of properties.
Buy and hold renting is less exciting. You should be able to determine a rate of return for your area based on comps and rental rates. The downside of renting is managing tenant issues and slow cycle time between purchases (boredom). One way to manage risk of really bad things (eviction, furnace, foundation, etc) with buy and hold is to have a larger number of properties. That is, you're bound to have unexpected repairs and vacancies. It is better to have several less expensive properties bringing in income while one is out of commission than to risk having a single expensive property out of commission.
One can certainly go broke with a bad rental purchase but I think flipping caries a greater risk. During the housing crash, flippers were the ones stuck with inventory they couldn't sell and debts they couldn't pay. Landlords in a reasonable market (not Detroit) can weather a storm like that of a few years as long as their original numbers made sense.