After reading some of the reviews about feeling the bars I was nervous... that being said I purchased it anyways and I am really happy with my purchase.  Just to be on the safe side, I put a thin piece of foam first and then added the mattress.  You cannot feel any bars.  I have a Lazy Boy sofa bed that a paid a lot of money for and the coil mattress was terrible.  Everyone complained who slept on it... now it feels great.  So it is definitely worth the risk to purchase it.  On a neat note... your children will love watching the mattress expand... you can even take a poll on how long they think it will take and get them to keep measuring it and at what time.