Earlier Jeff Brown posted some comments
on some new features of MbUnit v3, which I responded to by how to answer the NUnit critics concerning isolation of test fixtures.
with what I think is a pretty good answer. I'll have to think it through for a bit.
I believe that my original question was not so much a question of the validity of the approaches, but that after reading the book, I found that I had not considered the original issue of isolation via new test fixture classes.
I started with NUnit as my first experience and not JUnit, so the set and tear down mechanisms were just 'what was' rather than what should be.
As I've said in my other posts, I am often constrained by decisions made from outside my organization and the choice of unit testing framework is no different so having the best arsenal of responses to the unavoidable battles for these types of choices is a good thing.