There's no reason why they should give any more trouble than a manual car. In fact, as a second-hand car, it is potentially more reliable than a manual; boy-racers don't buy automatics, the electronics monitoring the gearbox will not permit you to over-rev or labour the engine and there's no clutch to ride for people too idle to use the handbrake, so there's far less chance that the car has been abused.
For inexperienced drivers there's less to worry about as they can't get caught in the wrong gear, no hill-starts to catch them out and it's almost impossible to stall them.