>1)  Simple to extend existing applications written in C with Ruby.
>2)  Great syntax
>3)  Blocks
>4)  DRb
>5)  Rails

Besides SWIG, py has several mature well-documented libraries for
extensions and inlining c/C++: CXX, boost, weave, pyrex:

http://cxx.sourceforge.net/
http://www.python.org/cgi-bin/moinmoin/boost_2epython_2fGettingStarted
http://www.cosc.canterbury.ac.nz/~greg/python/Pyrex/
http://www.scipy.org/documentation/weave/

Syntax: Mr. Fulton's Ruby Way, appendix B compares Ruby 1.6, python 2.2
(py 2.4's not materially different from 2.2, whereas rb 1.8 was a big
leap forward).  Python's oft-criticized O-O
warts_or_philosophical_choices: no truly class-private declaration
("__methORattrib_name" is just a name-mangling procedure; "self" must
always 1st param in method defs; duplication between function and
method libs, e.g. for string processing. You could look at Codezoo, see
waht those folks have picked as well coded, documented, &tested ruby
and python components.

blocks: Guido's definitely paying attention, read the (accepted) PEP:
http://www.python.org/peps/pep-0343.html
+1 for ruby!

the python Drb analog would be pyro:
http://directory.google.com/Top/Computers/Programming/Languages/Python/Modules/Distributed_Computing

rails analogs: Django, Subway i know nothing about.  Rails kicks ass,
just like every intelligent person proclaims out loud at least 1x/hour!