StackedObjectProxy (which I have mixed feelings about), data mapper pattern (basically SQLAlchemy kicking ass), and the kicker: an integrated debugger.
There are others I've noticed, but that's off the top of my head. Of course, Pylons falls short in some other areas.
Well, it's been a while, but I'll see what I can recall. I fought with them a lot during one project, though it may have been due to a lack of understanding. You can view a bit of that struggle here: http://groups.google.com/group/pylons-discuss/browse_thread/...
The main issue is that they're poorly documented and don't seem that pythonic to me. They are not standard python objects, and as such they are difficult to debug. Hopefully the situation has improved in the past year or so.
Almost all of pylons' nice features come from it being built on some of the best python projects out there. Pylons itself isn't much more than glue, but as a packaged deal, it can't be beat.
