After looking at the demo, we bit on purchasing IPB two weeks ago. Our staff installed the application on a sandbox and within a week's time had determined that while IPB is a solid product, the core files do not suit our project. We inquired about a refund policy and were informed that there was none. We are now the proud owner of a $150 forum application that will likely never be used.
Double check, triple check and quadruple check everything before you purchase. There's no turning back.