This is VERY interesting but I have always thought there is a fundamental problem with these mind mapping techniques at university level which is that the detail can be too brief to get into the nuances of the text for an essay and then there is the matter of keeping a record of where sources used are from for referencing and a bibliography. For that reason I have never in the past been comfortable with it even while cursing the using of traditional linear notes. If people like Tony Buzan and yourself can show how that concern can be addressed then I'm all for it.
I definitely agree that mind maps are probably not the most appropriate tool for detailed notes but then that's not (IMHO

) what there for, even if they do quite often get used as such.
They are cognitive frameworks not notes in and of themselves they are meant to act as ways of connecting more detailed ideas together I tend to think of them as kind of "meta notes".
The way I tend to use them is as follows:
1.) read up on topic making sort of high level map of how stuff fits together not trying to absorb everything.
2.) Any points that I find difficult or that I think need more explanation I make notes on. I try to keep them brief (if I'm writing them manually I use those little 6 X 4 index cards, on each one I put a reference normally a number. )
3.) Add the references to the the more detailed notes to the mind map.
I find that this kind of hybrid approach works best for me because I have the more detailed notes if I need them but I can also see how everything fits together which helps me with recall.
I'm not saying its the best way of doing it but it works for me

.