Hi,
Ventolin HFA inhaler is
Albuterol. No real difference, the same drug is in both ventilators that relaxes throat muscles to increase ability to breath. You will have to do the research yourself but many of the differences are based on the propellant used (older ones use CFC's that burn holes in the ozone layer) and are being phased out. The Ventolin inhaler also comes in a form that has a counter on it which might be helpful for monitoring your childs usage. Inhalers are commonly misused by kids. Either way, don't fear the new product it is better for the environment. Also, many of the differences between Albuterol based inhalers are in terms of cost. Your insurance might pay for most or all of a generic brand while making you pay for 80 percent of ventolin.
Disclaimer, I use Ventolin HFA for occasional exorcise induced asthma.