The licensing issue was due to the latest release bundling more features and raising the cost of ownership. We are talking tiny money for a real business, but hobby-type site owners were enraged.
vBulletin CAN be resource intensive. While there are steps you can take to speed it up as your activity level increases, be prepared to throw hardware at it. The one type of community that I wouldn't recommend vBulletin for is a very busy site with little or no revenue. As long as your site revenue scales with your level of user activity, you should be able to support vB's hardware demands without a problem.