I've always agreed with Mercurial's mantra 1, however, now that Mercurial comes bundled with the rebase extension and it is a popular practice in git, I'm wondering if it could really be regarded as a "bad practice", or at least bad enough to avoid using. In any case, I'm aware of rebasing being dangerous after pushing.
OTOH, I see the point of trying to package 5 commits in a single one to make it look niftier (specially at in a production branch), however, personally I think would be better to be able to see partial commits to a feature where some experimentation is done, even if it is not as nifty, but seeing something like "Tried to do it way X but it is not as optimal as Y after all, doing it Z taking Y as base" would IMHO have good value to those studying the codebase and follow the developers train of thought.
My very opinionated (as in dumb, visceral, biased) point of view is that programmers like rebase to hide mistakes... and I don't think this is good for the project at all.
So my question is: have you really found valuable to have such "organic commits" (i.e. untampered history) in practice?, or conversely, do you prefer to run into nifty well-packed commits and disregard the programmers' experimentation process?; whichever one you chose, why does that work for you? (having other team members to keep history, or alternatively, rebasing it).
1 per Google DVCS analysis, in Mercurial "History is Sacred".