[ksdkkdddd]

In my experience a package's ability to cope with a complex uninstall scenario generally improves with the initial upgrade - or any upgrade for that matter - (for example, sometimes dist-upgrade-specific issues are only discovered by the maintainer as part of the coordination for a release) and so (in my experience) the reliability of the "dist-upgrade" is usually increased by doing an "upgrade" first. Dist-upgrade is one of those things that "should work" of it's own accord, but there are ways of increasing the odds; I have found a pre-"dist-upgrade" upgrade is one. (Sometimes I'm impatient and only upgrade apt/aptitude before a dist-upgrade though.)

I would say it makes more of a difference on systems that are infrequently upgraded in general since a few points away from the current versions aren't going to contain many differences anyways, but I'd certainly be more hesitant to dist-upgrade from a .0 release (6.0 to 7.x, for example). I'd almost rather clean-install in that scenario since it amounts to a similarly-sized download.