My memory was fuzzy in the baz/bazaarNG distinction. Thanks for clarifying.
On whether the reliability of storage and Martin Pool's regard of it... I have an anecdote :-)
I was sitting at Martin Pool's presentation in linux.conf.au 2006 (Dunedin, NZ). From the back of the room, in the QA part of the session, someone asked: "so, is it ready for real work? You see, I have this large codebase that's been developed for 25+ years. After several VCS migrations, it's in CVS with a messy repo due to migrations. We are a widely distributed team, and we are hurting. Should I be migrating to bzr now?"
Martin looked rather uncomfortable with the question, and muttered something like "not really, not yet". He had already been less than reassuring when I had asked whether Bazaar storage was delta-centric (darcs-like) or snapshot centric (git-like).
The "is it ready for real workdd?" question had come from Jim Gettys, who I did not know personally at the time. After the talk I asked him whether he had been talking about X.org and whether he could give me access to those messy X.org CVS repos. I would try importing them into git, and we could see if he liked the outcome.
It was the start of a long hard road -- it led to many improvements to git- cvsimport, yet the migration was done with parsecvs (written by Keith Packard).
I was at linux.conf.au to run a workshop on git; Linus joined us, so it stretched from 2 to 4hs. We had a much smaller room assigned than Bazaar, but you could feel we were rocking and rolling :-) I believe Matt Mackall was there too, talking about Mercurial, but I missed it.
This happened long ago -- and this is how I remember it. Quotes are as best as I can recall.
In my view, 2006/2007 was the time where the overall trends in the DVCS space got established; x.org migrated to git, Mozilla ran high profile bakeoffs between DVCSs, etc. And at that time Bazaar was on unfortunately on unsure footing (bad timing!). As a result, Git and Mercurial generally stole the show...