is it safe to jump on a BOSU and not have the seams bust out on you? is there a weight limit?

For all practical pruposes no. The BOSU is made with a Burst-Resistant material and was designed to be used by professional athletes, some weighing as much as 350lbs or more. Also, the BOSU has a platform that is 25 inches in diameter and it inflates into a hemisphere 12 high when fully inflated. There are other sizes. This is the most common BOSU size found in health clubs.