When I first met my surgeon he asked me which surgeries I had heard of, I spouted them all off, including the balloon and he told me about each one but for the balloon he said something along the lines "that one is pointless".
There was a guy on Fat Doctor who wasnt well enough to have main surgery but badly needed to drop the weight to save his life because of his heart, so they fitted the balloon but it really didnt do all that much for him and when that programme ended he was in pretty much the same position as he was before the balloon.
I THINK it is mainly used to get a very very heavy patients weight down to a level of where they can have surgery that is more long lasting as once it is removed the weight will come back on.
Doesnt seem like something to do as a long term solution. Have you checked if your BMI is high enough for a band, maybe that is still an option, it sure is more long term.
Steph xx