Cake is another popular one, and I did look briefly at it, just by reading through their docs. It looked decent, but something struck me as being a little 'messy' though i couldn't put my finger on it.
Also, I hear performance could be a little lacking with Cake, but I can't substantiate that, and where I got it from. Symfony has some issues too, because of Propel, but that's being worked on (AFAIK).
Zend will probably be very good. The problem is, I'll bet it's at least a year until it's stable enough to be used in production. Symfony is not at 1.0 either, but it's currently far more mature and complete, and has gotten some rave reviews (though there sure are a lot of YAML files for configuration...).
