Well, seeing as I'm dissatisfied with Zend_Db_Table
after being spoiled by LINQ, I'm looking to get started learning an ORM with PHP. General consensus seems to be that Doctrine and Propel are the only good ones for serious use -- and whatever my opinion, I'd like to use something at least moderately popular so that people in the future can look at this app I'm working on without having an head explosion :P
I'm currently leaning towards Propel because it's documentation seems to be a bit more complete, and it supports the nested set model (also called "modified preorder tree transversal model") right out of the box. However, I like Doctrine's use of namespaces and other PHP 5.3 features, and it seems to be a bit more popular.
From those who have used either ORM with Zend Framework, which meshes better with the existing framework (if either)? What kind of issues should I watch out for using either framework with Zend?