I can only tell you what it was like in my experiences; not what it’s like today. For all I know Bill has changed his methods and style in his foundation.
Over the years at Microsoft meetings to review plans and status on products morphed into something that, by the last few years that Bill was still at the company, caused product teams enormous amounts of grief and worry. My experience of Billg meetings were that he would ask the three vital questions that you hadn’t thought of, and that, in hindsight, were obviously critical to your plans. How he managed to do that I don’t know.
He was always late. His schedule was always crammed–it was tough to schedule time on his calendar. You’d be in the room all set and waiting for him to show up. When he did it was all business, no small talk, no fooling around. You’d start the presentation and he’d interrupt with questions; he wouldn’t wait until you were done.
Bill was (and probably still is) super analytical. What you couldn’t do in a meeting with Bill is speak to your intuition or feelings about stuff; what he wanted to know was what facts could you bring to the table. Everybody can argue about their hunches, or intuition, or best guess; nobody can argue with data. So instead of saying “We think we customers will really value extended database capabilities in Excel” you would need to say, “Here are the results of extensive customer feedback, help desk issues, focus groups, and market surveys that tell us that the most common use for Excel is to create non-relational databases, basically flat files.”