NeXus and imgCIF / CBF are both concerned with similar problems, but have taken very different approaches.
Clearly, the different groups see the situation somewhat differently, but it is worthwhile proposing that two formats might each be best at tackling notably different aspects of data storage.
imgCIF / CBF is a much simpler and much more portable solution, and is very efficient. Thus, imgCIF / CBF should concentrate on truly international data exchange and front-end data acquisition systems.
NeXus, which uses HDF is a much more complicated, but also much more powerful system. HDF was designed for supercomputing environments. Thus, (I propose) NeXus should concentrate on using this power for such tasks as visualization of very complicated datasets in a more "local": environment. ("Local" does not have to mean physically local, but a more limited scientific community with similar resources.)
Both groups have agreed to maintain contact, and to coordinate activities such that exchange from one format to another will be as straightforward as possible, and without loss of information e.g. a one to one correspondance between stored data items, using the same definitions wherever possible.