I have OpenSuse 11.2 64-bit and Calibre instalation from their site (binary) was flawless and it works great, just make sure you have got all dependencies mentioned on their site.
my issue with the python installer from that site is that there's no un-install procedure. you'll have to follow the install log and manually delete everything that was installed, from various locations. i'm not sure if there's an update script, but oS repos are generally easier because all that's taken care of.
My problem is that for KDE 4.5 I have had to update the python-sip package to avoid dependency conflicts.
The issue now is what would be the way to make calibre run with this newer python-sip version.
i would be surprised if the same dependency on python-sip wouldn't exist when calibre is installed using that python script.

updating the python-sip package really isn't that hard; you'd just have to add the repo i mentioned. but it's up to you of course: trouble this way, trouble that way. pick your poison...

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phani.