At some point in time in my life (I don't know when), I started to ignore the UI of various OSes. Most of my time I spent in an IDE, browsers, and occasionally a communication software (Outlook, LotusNotes, e-mail client, whichever floats).
On the other hand, I thought people install Python libraries either directly downloading the distributions or via easy_install? I never install modules from apt/yum.
shrug - Like I said, it's a matter of aesthetics and usability for me. I've never met a Linux UI I liked (except for XFCE a long time ago), and I go out of my way not to use non-native apps on OSX. It's all about personal preference. I also dabble in design and UI/UX, and have for some time, maybe that's why.
It depends on the communities. For web developers, which depend on few compiled dependencies, this works well. For some other communities, like scipy community, not so much. Incidentally, mac os x is the worst platform to support ATM in that aspect, because of incompatibilities between OS X versions, python versions (mac os x vs python.org, all ABI incompatible), etc... Even windows is easier to handle at this point.
On the other hand, I thought people install Python libraries either directly downloading the distributions or via easy_install? I never install modules from apt/yum.