I did not really know Barbara on a personal basis, although we corresponded over the publishing of the NBI course,Basic Principles of Objectivism, in print book format in 2009 (The Vision of Ayn Rand: The Basic Principles of Objectivism, By Nathaniel Branden with a Foreward by Barbara and an Afterward by Nathaniel). She did, with Nathaniel, convince the publisher, James Peron, to let it be available through Amazon.
I first saw Barbara, in the company of Nathaniel, Ayn, and Frank, sittin together at the side of the hotel ballroom that they had rented for the opening lecture of the NBI course. This was in 1967 or early 1968. Anyway, Barbara was striking. I recalled an article in Look magazine from the early 1960's which had an article on Rand and on the lectures from NBI. Naturally, it was not a favorable article, but it had some interesting pictures of Rand and the Brandens. I believe the photo that included Barbara described her in the caption as an "ice cool blond who could easily pass as a fashion model. My memory is hazy about the exact wording. Anyway, they were right in whatever compliments that they described her with. Personally, I would say, "Drop-dead gorgeous!"
I met her very briefly at a reception in Chicago in 1986, when her book first was published. She was signing copies and I asked her if she had seen the extremely nasty "letter" that Peter Schwartz had sent out to subscribers of The Intellectual Activist, which he owned at that time. Not a review, but an attack on both of the Brandens, describing them as "lice." A really charming fellow. Anyway, Barbara said that she had seen it, but did not think that it really mattered.
Some years later I saw her delivering lectures at some of The Atlas Society conferences and had a chance to talk with her. As always, she responded to any questions directly and politely, even if they were hostile. This was in contrast to Ayn, who did not suffer fools gladly, and told them so if they had asked her what she viewed as a foolish or hostile question.
Some her last lectures that she gave to The Atlas Society conferences dealt with the continued cultish and siege mentality exhibited by some of the ARIans. I think that many of those lectures by Barbara at TAS are available on their website and/or in audio format.
In conclusion, I would say that Barbara was a genuinely a warm and friendly Lady (with a capital L), a skilled lecturer and a brilliant conversationalist, who was in many ways the living personification of what an Objectivist should be.