I had Invision Board for my family forum when it was free. Then they suddenly decided to ask a price for it, so when PHP6 was installed on my server and the forum didn't work anymore, I would have to pay to upgrade the forum.
So I switched to Simple Machines Forum instead, where they have a converter from IPB (and lot of others) to SMF for free as well.
It's a common but dirty marketing trick that I do not like, and I therefore consider Invision Power to be uncool.
