It's difficult to explain what it is, precisely, about python RegExes that make them awkward, and perhaps if I had never encountered the syntatic regex sugar that is perl, I would have never noticed. But, as a total python advocate and frequent writer of python scripts - I still find my brain hitting wait-states that don't occur in perl when I need to pattern match. I can live with that because of the 50+ things that make python so much better (for me) than Perl (Hash of Array / Array of Hash at the top of the list) - but it's sad that I still don't regex in Python as fluidly as perl.

I think the first hint that Python wasn't developed with RegEx users in mind would be that in the 700 Page "Learning Python, 3rd Edition" - Regular expressions aren't even mentioned in the Index.