we have been using Propel with Symfony for 2 years and Doctrine with Symfony for more than 1 year. I can say that moving to ORM with MVC framework was the best step we've made. I would recommend sticking with Doctrine eventhough it takes some time to learn how to work with it. In the end you'll find your code more readable and flexible.
If you're searching for some place where to start, I would recommend Symfony Jobeet tutorial http://www.symfony-project.org/jobeet/1_4/Doctrine/en/ (chapters 3, 6 covers the basics) and of course Doctrine documentation.
As I wrote above we have been using Doctrine for some time now. To make our work more comfortable we developed a tool called ORM Designer (www.orm-designer.com) where you can define DB model in a graphical user interface (no more YAML files :-), which aren't btw bad at all). You can find there also some helpful tutorials.
