Thanks for the quick response. My company already approved the purchase of Mindjet. Unfortunately, when David Allen, in the webcasts, tries to differentiate the uses for the two products, the relevant portion is removed, interrupted or otherwise not understandable. Therefore, I am trying to learn the difference, but other web sites contain useless information about old products. Moreover, both companies do not refer, for obvious reasons, to their competitor's products.
FWIW, I think they only sort of compete. Mindjet makes a feature-rich mind-mapping tool. If you are at all familiar with mind-mapping, you can get started easily and learn features as needed. Personal Brain has some overlap, but is more of a visual, associative database. Stuff goes in, and you hope you and the program together can figure out something. I used to use Mindjet, but they did not move quickly enough into today's world of small, fast tools and BYOD. Their market, I suspect, is mostly corporate now. I tried Personal Brain, but it's not something I need or want. I want tools that have as light a footprint as possible, and play well with other programs cross-platform. I use MindNode on Mac, iPhone, and iPad for mind-mapping. If you want to do mind-mapping on a PC in a corporate, collaborative environment, Mindjet seems like the logical choice.