I don't use Python much at all, it didn't seem to have any advantages over Perl, not that Perl is the best language ever... but good enough that Python held no interest other than curiousity in trying a new language.
However! I have tried to keep up with what is going on, and I got the distinct impression that the biggest problem with the 3.x branch was its lack of backwards compatibility. Perl6 looks to be taking even longer to come to life, but at least they have made provisions for compatibility packages, from what I think I remember reading, so that you could run perl5 packages in perl6 programs with at least mostly good prospects of succeeding.
If Python 2.x ---> 3.x really does have no compatibility provisions, if you really do have to run either 2.x or 3.x, and there is no way to include 2.x packages in 3.x, that seems incredibly brain dead to me. If there is no migration path, how are people supposed to migrate? I am serious in asking that. Was there any kind of plan for how people could switch from 2.x to 3.x? Were package maintainers supposed to maintain two versions of everything for several years? Were production developers supposed to maintain two versions of their code for several years? It all seems as if someone (BDFL?) had unrealistic ideas of how much spare time real life provides for such fantasies.