Frameworks are extremely helpful for organising large projects and/or projects with “many hands in the pot.” Most developers who work on sufficiently large projects end up writing some or all of the components present in the major frameworks at some point (e.g., an object-relational mapping component so you can interact with your database data as objects).
That said, it can be a major pain to install a framework in a shared hosting environment. Rails is notorious for not playing well in these environments and the creator of Rails has even come out and said it’s not a high priority to fix the problem.
Anyway, to more directly answer your question, Symfony is a Rails clone (at least as far as PHP allows it to be [PHP can’t do everything that Ruby can, so the frameworks are not 100% the same]). It has lots of nice features that make development faster and easier once you grok the “Symfony Way.” I haven’t used Cake for any serious work, but in my playing around with it, it seems to have most if not all of the features that Symfony does.
My experience is similar to johnpowell; Cake is really easy to set up in a shared hosting environment. So, if that’s a requirement for your project, take that into account.
Now, are you required to use PHP? Django and Pylons are 2 kick arse frameworks that run on Python. And, perhaps you could work in Rails, rather than “settling” for a clone. In my experience, Python and Ruby are both more enjoyable languages to work in than PHP. Of course, PHP has the advantage of ubiquity.
FWIW, Python versus Ruby versus PHP has been hashed out before.