I'm currently working with TurboGears. I evaluated pylons, django and web.py a year ago and made my decision. Here is a summary of my opinions (note from a year ago).
pylons: didn't really like the lack of decorators, didn't seem to be an ORM of choice, docs looked weak although the wiki was well stocked with recipies
django: really well documented. Seemed to be HUGE and I felt intimidated by it. It wasn't clear to me I could strip it down to what I needed. Didn't seem very modular, you can only use the Django ORM and templating engine.
web.py: Far to simple for my needs, you need to build nearly everything from scratch, simple to learn because there is nothing there!
I chose Turbo Gears because it seemed easier to chose the components you want to use. The idea that the TurboGears community picks best of breed python components and integrated them really appealed to me. This is both good and bad but in general I think it's been good for the project.
A year later and I haven't been disappointed. The TG community is really friendly as well :) TG is working with the pylons team for the next version of TurboGears and I know there has been a lot of code sharing between the groups.
"Didn't seem very modular, you can only use the Django ORM and templating engine."
Very common misunderstanding. You can use Django with SQLAlchemy (I have done in the past). You can use Django with Genshi, or Cheetah, or whatever template engine you like (I would strongly recommend using something like Genshi for outputting XML). It's usually better to stick with the Django ORM though as it will let you use many of the excellent extension applications for Django (such as django-mptt, django-tagging or the Django admin package). The same is not true for the Django template system - replacing it with something else has no disadvantages at all that I can think of.
pylons: didn't really like the lack of decorators, didn't seem to be an ORM of choice, docs looked weak although the wiki was well stocked with recipies
django: really well documented. Seemed to be HUGE and I felt intimidated by it. It wasn't clear to me I could strip it down to what I needed. Didn't seem very modular, you can only use the Django ORM and templating engine.
web.py: Far to simple for my needs, you need to build nearly everything from scratch, simple to learn because there is nothing there!
I chose Turbo Gears because it seemed easier to chose the components you want to use. The idea that the TurboGears community picks best of breed python components and integrated them really appealed to me. This is both good and bad but in general I think it's been good for the project.
A year later and I haven't been disappointed. The TG community is really friendly as well :) TG is working with the pylons team for the next version of TurboGears and I know there has been a lot of code sharing between the groups.
That's my 2p, good luck.